John Maynard Keynes, 1st Baron Keynes, CB (5 June 1883 – 21 April 1946) was a British economist whose ideas have profoundly affected modern macroeconomics and social liberalism, both in theory and practice. He advocated interventionist economic policy, by which governments would use fiscal and monetary measures to mitigate the adverse effects of business cycles, economic recessions, and depressions. His ideas are the basis for the school of thought known as Keynesian economics, and its various offshoots.

In the 1930s, Keynes spearheaded a revolution in economic thinking, overturning the older ideas of neoclassical economics that held that free markets would automatically provide full employment as long as workers were flexible in their wage demands. Following the outbreak of World War II, Keynes's ideas concerning economic policy were adopted by leading Western economies. During the 1950s and 1960s, the success of Keynesian economics was so resounding that almost all capitalist governments adopted its policy recommendations. In 1999, Time magazine included Keynes in their list of the 100 most important and influential people of the 20th century, commenting that: "His radical idea that governments should spend money they don't have may have saved capitalism". Keynes's influence waned in the 1970s, partly as a result of problems that began to afflict the Anglo-American economies from the start of the decade, and partly due to critiques from Milton Friedman and other economists who were pessimistic about the ability of governments to regulate the business cycle with fiscal policy. However, the advent of the global financial crisis in 2007 has caused a resurgence in Keynesian thought. Keynesian economics has provided the theoretical underpinning for the plans of President Barack Obama of the United States, Prime Minister Gordon Brown of the United Kingdom, and other global leaders to ease the economic recession. Keynes is widely considered the father of modern macroeconomics, and by various commentators such as economist John Sloman, the most influential economist of the 20th century. In addition to being an economist, Keynes was also a civil servant, a patron of the arts, a director of the Bank of England, an advisor to several charitable trusts, a writer, a private investor, an art collector, and a farmer. Keynes was bisexual, openly acknowledging the homosexual relationships he had with other men. In 1925, he married the Russian ballerina Lydia Lopokova. Of towering stature, Keynes stood at six foot, six inches.

John Maynard Keynes was born in Cambridge to a middle-class family. His father, John Neville Keynes, was a lecturer at Cambridge University and his mother Florence Ada Keynes a local social reformer. Keynes was the first born, and was followed by two more children - Geoffrey Keynes in 1887 and Margaret Neville Keynes in 1890. According to economist and biographer Robert Skidelsky, Keynes' parents were loving and attentive, but not smotheringly so. They remained in the same house throughout their lives, where the children were always welcome to return. Keynes would receive considerable support from his father; including expert coaching to help him pass his scholarship exams and financial help both as a young man and when he was nearly wiped out at the onset of Great Depression in 1929. Keynes' mother made her children's interests her own, and according to Skidelsky, "because she could grow up with her children, they never outgrew home". Keynes had his early education at home and in kindergarten. He attended St Faith's preparatory school as a day pupil from 1892-1897. Teachers described Keynes as brilliant, but on occasion, careless and lacking in determination. His health was often poor during this period, leading to several long absences.

Keynes won a scholarship to study at Eton, where he displayed talent in a wide range of subjects, particularly mathematics, classics and history. Despite his middle-class background, Keynes mixed easily with upper-class pupils. In 1902 Keynes left Eton for King's College, Cambridge, to study mathematics. The famous Alfred Marshall begged Keynes to become an economist, although Keynes's own inclinations drew him towards philosophy – especially the ethical system of G.E. Moore. Keynes was an active member of the semi-secretive Cambridge Apostles society, a debating club largely reserved for the brightest students. Like many members, Keynes retained a bond to the club after graduating and continued to attend occasional meetings throughout his life. Before leaving Cambridge, Keynes became the President of the Cambridge University Liberal Club. In May 1904 he received a first class B.A. in mathematics. Aside from a few months spent on holidays with family and friends, Keynes continued to involve himself with the university over the next two years. He took part in debates, further studied philosophy and attended economics lectures informally as a graduate student. He also studied for his 1905 Tripos and 1906 Civil Service exams.

The economist Harry Johnson wrote that the optimism imparted by Keynes's early life is key to understanding his later thinking. Keynes was always confident he could find a solution to whatever problem he turned his attention to, and retained a lasting faith in the ability of government officials to do good. Keynes optimism was also cultural, in two senses – he was of the last generation raised by an empire still at the height of its power, in its own eyes and by much of the world (at least outwardly) seen as preeminent in both power and benevolence. Keynes was also of the last generation who felt entitled to govern by culture, rather than by expertise. According to Skidelsky, the sense of cultural unity current in Britain from the 19th century to the end of World War I, provided the well educated a framework with which to set various spheres of knowledge in relation to each other and to life, enabling them to confidently draw from different fields when addressing practical problems.

Keynes's Civil Service career began in October 1906, as a clerk in the India Office. He enjoyed his work at first, but by 1908 had become bored and resigned his position to return to Cambridge and work on probability theory, at first privately funded only by two Dons at the university – his father and the economist Arthur Pigou. In 1909 Keynes's published his first professional economics article in the Economics Journal, about the effect of a recent global economic downturn on India. Also in 1909, Keynes accepted a lectureship in economics funded personally by Alfred Marshall. Keynes's earnings rose further as he began to take on pupils for private tuition, and on being elected a fellow. In 1911 Keynes was made editor of the Economic Journal. By 1913 he had published his first book, Indian Currency and Finance. He was then appointed to the Royal Commission on Indian Currency and Finance – the same topic as his book – where Keynes showed considerable talent at applying economic theory to practical problems.

The British Government called on Keynes's expertise during the First World War. While he did not formally re-join the civil service in 1914, Keynes travelled to London at the government's request a few days before hostilities started. Bankers had been pushing for the suspension of specie payments – the convertibility of bank notes into gold – but with Keynes's help the Chancellor of the Exchequer (then Lloyd George) was persuaded that this would be a bad idea, as it would hurt the future reputation of the city if payments were suspended before absolutely necessary. In January 1915 Keynes took up an official government position at the Treasury. Among his responsibilities were the design of terms of credit between Britain and its continental allies during the war, and the acquisition of scarce currencies. According to economist Robert Lekachman, Keynes's "nerve and mastery became legendary" due to his performance of these duties, as in the case where he managed to assemble — with difficulty — a small supply of Spanish pesetas. The secretary of the Treasury was delighted to hear Keynes had amassed enough to provide a temporary solution for the British Government. But Keynes did not hand the pesetas over, he sold them all to break the market: his boldness paid off, as pesetas then became much less scarce and expensive. In the 1917 King's Birthday Honours, Keynes was appointed Companion of the Order of the Bath for his wartime work, and his success led to the appointment that would have a huge effect on Keynes's life and career; Keynes was appointed financial representative for the Treasury to the 1919 Versailles peace conference. He was also appointed Officer of the Belgian Order of Leopold.

Keynes's experience at Versailles was influential in shaping his future outlook, yet it was not a successful one for him. Keynes's main interest had been in trying to prevent Germany's compensation payments being set so high it would traumatize innocent German people, damage the nation's ability to pay and sharply limit her ability to buy exports from other countries - thus hurting not just Germany's own economy but that of the wider world. Unfortunately for Keynes, conservative powers in the coalition that emerged from the 1918 coupon election were able to ensure both Keynes himself and the Treasury were largely excluded from formal high-level talks concerning reparations. Their place was taken by the Heavenly Twins - the Judge Lord Sumner and the Banker Lord Cunliffe whose nickname derived from the "astronomically" high war compensation they wanted to demand from Germany. Keynes was forced to try to exert influence mostly from behind the scenes. The three principal players at Versailles were Britain's Lloyd George, France's Clemenceau and America's President Wilson. It was only Lloyd George to whom Keynes had much direct access; until the 1918 election he had some sympathy with Keynes's view but while campaigning had found his speeches were only well-received by the public if he promised to harshly punish Germany, and had therefore committed to extracting high payments. Lloyd George did however win some loyalty from Keynes with his actions at the Paris conference by intervening against the French to ensure the dispatch of much-needed food supplies to German civilians. Clemenceau also pushed for high reparations; generally France argued for an even more severe settlement than Britain. Wilson initially favoured relatively lenient treatment of Germany – he feared too harsh conditions could foment the rise of extremism, and wanted Germany to be left sufficient capital to pay for imports. To Keynes's dismay, Lloyd George and Clemenceau were able to pressure Wilson to agree to very high repayments being imposed. Towards the end of the conference, Keynes came up with a plan that he argued would not only help Germany and other impoverished central European powers but also be good for the world economy as a whole. It involved the writing down of war debts which would have the effect of increasing international trade all round. Lloyd George agreed it might be acceptable to the British electorate. However America was against it, the US then being the largest creditor and by this time Wilson had started to believe in the merits of a harsh peace as a warning to future aggressors. So despite his best efforts, the end result of the conference was a treaty which disgusted Keynes both on moral and economic grounds, and led to his resignation from the Treasury. Keynes's analyses on the predicted damaging effects of the treaty appeared in the highly influential book, The Economic Consequences of the Peace, published in 1919. This work has been described as Keynes's best book, where he was able to bring all his gifts to bear - his passion as well as his skill as an economist. In addition to economic analysis, the book contained pleas to the reader's sense of compassion:

I cannot leave this subject as though its just treatment wholly depended either on our own pledges or on economic facts. The policy of reducing Germany to servitude for a generation, of degrading the lives of millions of human beings, and of depriving a whole nation of happiness should be abhorrent and detestable,--abhorrent and detestable, even if it were possible, even if it enriched ourselves, even if it did not sow the decay of the whole civilized life of Europe.

Also present was striking imagery such as "...that year by year Germany must be kept impoverished and her children starved and crippled..." along with bold predictions which were later justified by events:

If we aim deliberately at the impoverishment of Central Europe, vengeance, I dare predict, will not limp. Nothing can then delay for very long that final war between the forces of Reaction and the despairing convulsions of Revolution, before which the horrors of the late German war will fade into nothing.

Keynes's predictions of disaster were borne out when the German economy suffered the hyperinflation of 1923, and again by the collapse of the Weimar Republic and the outbreak of World War II. Only a fraction of reparations were ever paid. The Economic Consequences of the Peace gained Keynes international fame, but also caused him to be regarded as anti-establishment – it was not until after the outbreak of World War II that Keynes was offered a directorship of a major British Bank, or an acceptable offer to return to government with a formal job. Keynes was still able to influence policy making however – through his network of contacts, his published works and by serving on government committees, including attending high-level policy meetings as a consultant.

Keynes had completed his Treatise on Probability before the war, but published it in 1921. The work was a notable contribution to the philosophical and mathematical underpinnings of probability theory, championing the important view that probabilities were no more or less than truth values intermediate between simple truth and falsity. Keynes developed the first upper-lower probabilistic interval approach to probability in chapters 15 and 17 of this book, as well as having developed the first decision weight approach with his conventional coefficient of risk and weight. In addition to his academic work, the 1920s saw Keynes active as a journalist selling his work internationally and working in London as a financial consultant. In 1924 Keynes wrote an obituary for his former tutor Alfred Marshall which Schumpeter called "the most brilliant life of a man of science I have ever read." Marshall's widow was "entranced" by the memorial, while Lytton Strachey rated it as one of Keynes's "best works".

In 1922 Keynes continued to advocate reduction of German reparations with A Revision of the Treaty. He attacked the post World War I deflation policies with A Tract on Monetary Reform in 1923 – a trenchant argument that countries should target stability of domestic prices, avoiding deflation even at the cost of allowing their currency to depreciate. The 1920s saw high unemployment in Britain even before the outbreak of the Great Depression - in addition to advocating depreciating the currency as a way to boost jobs by making British exports more affordable, Keynes was from 1924 to start recommending a fiscal response to unemployment by means of government spending on public works. During the 20's Keynes' pro stimulus views had only limited effect on policy makers and mainstream academic opinion - according to Minsky one reason was that at this time his theoretical justification was "muddled". The Tract had also called for an end to the gold standard. Keynes advised it was no longer a net benefit for countries such as Britain to participate in the gold standard, as it ran counter to the need for domestic policy autonomy. It could force countries to pursue deflationary policies at exactly the time when expansionary measures were called for to address rising unemployment. The Treasury and Bank of England were still in favor of the gold standard and in 1925 they were able to convince the then Chancellor Winston Churchill to re-establish it, which had a depressing effect on British industry. Keynes responded by writing The Economic Consequences of Mr. Churchill and continued to argue against the gold standard until Britain finally abandoned it in 1931.

Keynes had begun a theoretical work to examine the relationship between unemployment, money and prices back in the 1920s. The work, Treatise on Money, was published in 1930 in two volumes. A central idea of the work was that if the amount of money being saved exceeds the amount being invested – which can happen if interest rates are too high – then unemployment will rise. This is in part a result of people not wanting to spend too high a proportion of what employers pay out, making it difficult, in aggregate, for employers to make a profit. At the height of the Great Depression, in 1933, Keynes published The Means to Prosperity, which contained specific policy recommendations for tackling unemployment in a global recession, chiefly counter cyclical public spending. The Means to Prosperity contains one of the first mentions of the multiplier effect. While it was addressed chiefly to the British Government, it also contained advice for other nations affected by the global recession. A copy was sent to the newly elected President Roosevelt and other world leaders. The work was taken seriously by both the American and British governments, and according to Skidelsky, helped pave the way for the later acceptance of Keynesian ideas, though it had little immediate practical influence. In the 1933 London Economic Conference opinions remained too diverse for a unified course of action to be agreed upon.

Keynesian-like policies were adopted by Sweden and Germany, but Sweden was seen as too small to command much attention, and Keynes was deliberately silent about the successful efforts of Germany as he was dismayed by their imperialist ambitions and their treatment of Jews. Apart from Great Britain, Keynes attention was primarily focused on the United States. In 1931, he received considerable support for his views on counter-cyclical public spending in Chicago, then America's foremost centre for economic views alternative to the mainstream. However, orthodox economic opinion remained generally hostile regarding fiscal intervention to mitigate the depression, until just before the outbreak of war. In late 1933 Keynes was persuaded by Felix Frankfurter to address President Roosevelt directly, which he did by letters and face to face in 1934, after which the two men spoke highly of each other. However according to Skidelsky, the consensus is that Keynes efforts only began to have a more than marginal influence on US economic policy after 1939.

Keynes's magnum opus, the General Theory of Employment, Interest and Money was published in 1936. It was researched and indexed by one of Keynes's favourite students, later the economist David Bensusan-Butt. The work served as a theoretical justification for the interventionist policies Keynes favored for tackling a recession. The General Theory challenged the earlier neo-classical economic paradigm, which had held that provided it was unfettered by government interference, the market would naturally establish full employment equilibrium. In doing so Keynes was partly setting himself against his former teachers Marshal and Pigou. Keynes believed the classical theory was a "special case" that applied only to the particular conditions present in the 19th century, his own theory being the general one. Classical economists had believed in Say's Law, which, simply put, states that "supply creates its own demand", and that in a free market workers would always be willing to lower their wages to a level where employers could profitably offer them jobs. An innovation from Keynes was the concept of price stickiness – the recognition that in reality workers often refuse to lower their wage demands even in cases where a classical economist might argue it is rational for them to do so. Due in part to price stickiness, it was established that the interaction of "aggregate demand" and "aggregate supply" may lead to stable unemployment equilibria – and in those cases, it is the state, and not the market, that economies must depend on for their salvation. The General Theory argues that demand, not supply, is the key variable governing the overall level of economic activity. Aggregate demand, which equals total un-hoarded income in a society, is defined by the sum of consumption and investment. In a state of unemployment and unused production capacity, one can only enhance employment and total income by first increasing expenditures for either consumption or investment. Without government intervention to increase expenditure, an economy can remain trapped in a low employment equilibrium – the demonstration of this possibility has been described as the revolutionary formal achievement of the work. The book advocated activist economic policy by government to stimulate demand in times of high unemployment, for example by spending on public works. The General Theory is often viewed as the foundation of modern macroeconomics. Historians agree that Keynes influenced U.S. president Roosevelt's New Deal, but disagree as to what extent. Deficit spending of the sort the New Deal began in 1938 had previously been called "pump priming" and had been endorsed by President Herbert Hoover. Few senior American economists agreed with Keynes through most of the 1930s. Yet his ideas were soon to achieve widespread acceptance, with eminent American professors such as Alvin Hansen agreeing with the General Theory before the outbreak of World War II.

Keynes's himself had only limited participation in the theoretical debates that followed the publication of the General Theory as he suffered a heart attack in 1937, requiring him to take long periods of rest. Hyman Minsky and other post-Keynesian economists have argued that as a result of this, Keynes's ideas were diluted by those keen to compromise with classical economists or to render his concepts with mathematical models like the IS/LM model (which they argue, distort Keynes's ideas). Keynes began to recover in 1939, but for the rest of his life his professional energies were largely directed towards the practical side of economics – the problems of ensuring optimum allocation of resources for the War efforts, post-War negotiations with America, and the new international financial order that was presented at Bretton Woods.

During World War II, Keynes argued in How to Pay for the War, published in 1940, that the war effort should be largely financed by higher taxation and especially by compulsory saving (essentially workers loaning money to the government), rather than deficit spending, in order to avoid inflation. Compulsory saving would act to dampen domestic demand, assist in channelling additional output towards the war efforts, would be fairer than punitive taxation and would have the advantage of helping to avoid a post war slump by boosting demand once workers were allowed to withdraw their savings. In September 1941 he was proposed to fill a vacancy in the Court of Directors of the Bank of England, and subsequently carried out a full term from the following April. In June 1942, Keynes was rewarded for his service with an hereditary peerage in the King's Birthday Honours. On 7 July his title was gazetted as Baron Keynes, of Tilton in the County of Sussex, and he took his seat in the House of Lords on the Liberal Party benches. As Allied victory began to look certain, Keynes was heavily involved, as leader of the British delegation and chairman of the World Bank commission, in the mid-1944 negotiations that established the Bretton Woods system. The Keynes-plan, concerning an international clearing-union argued for a radical system for the management of currencies. He proposed the creation of a common world unit of currency, the Bancor and of new global institutions — a world central bank and the International Clearing Union. Keynes envisaged these institutions managing an international trade and payments system with strong incentives for countries to avoid substantial trade deficits or surpluses. The USA's greater negotiating strength, however, meant that the final outcomes accorded more closely to the less radical plans of Harry Dexter White. According to US economist Brad Delong, on almost every point where he was overruled by the Americans, Keynes was later proved correct by events.

The two new institutions, later known as the World Bank and IMF, were founded as a compromise that primarily reflected the American vision. There would be no incentives for states to avoid a large trade surplus, instead the burden for correcting a trade imbalance would continue to fall just on the deficit countries, which Keynes had argued were least able to address the problem without inflicting economic hardship on their populations. Yet Keynes was still pleased when accepting the final agreement, saying that if the institutions stayed true to their founding principles, "the brotherhood of man will have become more than a phrase."

From the end of the Great Depression to the mid-1970s, Keynes provided the main inspiration for economic policy makers in Europe, America and much of the rest of the world. While economists and policy makers had become increasingly won over to Keynes's way of thinking in the mid and late 1930s, it was only after the outbreak of World War II that governments started to borrow money for spending on a scale sufficient to eliminate unemployment. According to economist John Kenneth Galbraith, then a US government official charged with controlling inflation, "one could not have had a better demonstration of the Keynesian ideas." The Keynesian Revolution was associated with the rise of modern liberalism in the West during the post-war period. Keynesian ideas became so popular that some scholars point to Keynes as representing the ideals of modern liberalism, like Adam Smith represented the ideals of classical liberalism. After the war Winston Churchill attempted to check the rise of Keynesian policy making in Great Britain. He had been influenced by Hayek's 1944 book The Road to Serfdom, and used rhetoric critical of the mixed economy in his 1945 election campaign. Despite his popularity as a war hero Churchill suffered a landslide defeat to Clement Attlee whose government's economic policy continued to be influenced by Keynes's ideas. In the late 1930s and 1940s, economists (notably John Hicks, Franco Modigliani, and Paul Samuelson), attempted to interpret and formalize Keynes' writings in terms of formal mathematical models. In a process termed "the neoclassical synthesis", they combined Keynesian analysis with neo-classical economics to produce Neo-Keynesian economics, which came to dominate mainstream macroeconomic thought for the next 40 years. By the 1950s, Keynesian policies were adopted by almost the entire developed world and similar measures for a mixed economy were used by many developing nations. By then, Keynes's views on the economy had become mainstream in the world's universities. Throughout the 1950s and 1960s, Europe, the United States and Japan enjoyed considerably lower unemployment and higher growth than they have had before or since. Professor Gordon Fletcher has written that the fifties and sixties, when Keynes' influence was at its peak, appear in retrospect as a Golden Age of Capitalism. In late 1965 Time magazine ran a cover article with the title inspired by a possibly tongue-in-cheek comment from Milton Friedman, a comment later echoed by U.S. President Richard Nixon, that "We are all Keynesians now". The article described the exceptionally favourable economic conditions then prevailing, and reported that "Washington's economic managers scaled these heights by their adherence to Keynes's central theme: the modern capitalist economy does not automatically work at top efficiency, but can be raised to that level by the intervention and influence of the government." The article also states that Keynes was one of the three most important economists who ever lived, and that his General Theory was more influential than the magna opera of other famous economists, like Smith's The Wealth of Nations.

Keynesian economics were officially discarded by the British Government in 1979, but forces had began to gather against Keynes's ideas over 30 years earlier. Friedrich von Hayek had formed the Mont Pelerin Society in 1947, with the explicit intention of nurturing intellectual currents to one day displace Keynesianism and other collectivist influences. Its members included Austrian School founder Ludwig von Mises along with the then young Milton Friedman. Initially the society had little impact on the wider world - Hayek was to say it was as if Keynes had been raised to sainthood after his death and that people refused to allow his work to be questioned. Friedman however began to emerge as a formidable critic of Keynesian economics from the mid 1950s, and especially after his 1963 publication of A Monetary History of the United States. On the practical side of economic life, big government had appeared to be firmly entrenched in the 1950s but the balance began to shift towards private power in the sixties. Keynes had written against the folly of allowing "decadent and selfish" speculator and financiers the kind of influence they had enjoyed after World War I. For two decades after World War II public opinion was strongly against private speculators, the disparaging label Gnomes of Zürich being typical of how they were described during this period. International speculation was severely restricted by the capital controls in place after Bretton Woods. Journalists Larry Elliott and Dan Atkinson say 1968 was a pivotal year when power shifted in the favour of private agents such as currency speculators. They pick out a key 1968 event as being when America suspended the conversion of the dollar into gold except on request of foreign governments, which they identify as when the Bretton Woods system first began to break down. Intellectually, attacks against Keynes's ideas had begun to gain significant acceptance from the early 1970s as they were able to make a credible case that Keynesian models no longer reflected economic reality. Keynes himself had included few formulæ and no explicit mathematical models in his General Theory. For commentators such as economist Hyman Minsky, Keynes's limited use of mathematics was partly the result of his scepticism about whether phenomena as inherently uncertain as economic activity could ever be adequately captured by mathematical models. Nevertheless, many models were developed by Keynesian economists, with a famous example being the Phillips curve which predicted an inverse relationship between unemployment and inflation. It implied that unemployment could be reduced by government stimulus with a calculable cost to inflation. In 1968 Milton Friedman published a paper arguing that the fixed relationship implied by the Philips curve did not exist. Friedman suggested that sustained Keynesian policies could lead to both unemployment and inflation rising at once — a phenomenon that soon became known as stagflation. In the early 1970s stagflation appeared in both the US and Britain just as Friedman had predicted, with economic conditions deteriorating further after the 1973 oil crisis. Aided by the prestige gained from his successful forecast, Friedman led increasingly successful attacks against the Keynesian consensus, convincing not only academics and politicians but also much of the general public with his radio and television broadcasts. The academic credibility of Keynesian economics was further undermined by additional criticism from other Monetarists trained in the Chicago school of economics, by the Lucas Critique and by attacks from Hayek's Austrian School. So successful were these attacks that by 1980 Robert Lucas was saying economists would often take offence if described as Keynesians. Keynesian principles fared increasingly poorly on the practical side of economics — by 1979 they had been displaced by Monetarism as the primary influence on Anglo-American economic policy. However many officials on both sides of the Atlantic retained a preference for Keynes, and in 1984 the Federal Reserve officially discarded monetarism, after which Keynesian principles made a partial comeback as an influence on policy making. Not all academics accepted the criticism against Keynes — Minsky has argued that Keynesian economics had been debased by excessive mixing with neo-classical ideas from the 1950s, and that it was unfortunate the branch of economics had even continued to be called "Keynesian". The American Prospect have argued it was not so much excessive Keynesian activism that caused the economic problems of the 1970s but the breakdown of the Bretton Woods system of capital controls, which allowed capital flight from countries the markets viewed as excessively Keynesian or socially progressive. Historian Peter Pugh has stated a key cause of the economic problems afflicting America in 1970s was the refusal to raise taxes to finance the Vietnam War, which was against Keynesian advice.

A more typical response was to accept some elements of the criticisms while refining Keynesian economic theories to defend them against arguments that would invalidate the whole Keynesian framework — the resulting body of work largely composing New Keynesian economics. In 1992 Alan Blinder was writing about a "Keynesian Restoration" as work based on Keynes's ideas had to some extent become fashionable once again in academia, though in the mainstream it was highly synthesized with Monetarism and other neo-classical thinking. In the world of policy making, free-market influences broadly sympathetic to Monetarism remained very strong at government level — in powerful normative institutions like the World Bank, IMF and US Treasury, and in prominent opinion-forming media such as the Financial Times and the Economist.

The Financial crisis of 2007–2010 led to public skepticism about the free market consensus even from some on the economic right. In March 2008, Martin Wolf, chief economics commentator at the Financial Times, announced the death of the dream of global free-market capitalism, and quoted Josef Ackermann, chief executive of Deutsche Bank, as saying "I no longer believe in the market's self-healing power." In the same month macroeconomist James K. Galbraith used the 25th Annual Milton Friedman Distinguished Lecture to launch a sweeping attack against the consensus for monetarist economics and argued that Keynesian economics were far more relevant for tackling the emerging crises. Economist Robert Shiller had begun advocating robust government intervention to tackle the financial crises, specifically citing Keynes. Nobel laureate Paul Krugman also actively argued the case for vigorous Keynesian intervention in the economy in his columns for the New York Times. Other prominent economists arguing for Keynesian government intervention to mitigate the financial crisis include George Akerlof, Brad Delong, Robert Reich, and Joseph Stiglitz. Newspapers and other media have also cited work relating to Keynes by Hyman Minsky, Robert Skidelsky, Donald Markwell and Axel Leijonhufvud. A series of major bail-outs were pursued during the financial crisis, starting on 7 September with the announcement that the U.S. government was to nationalize the two government-sponsored enterprises which oversaw most of the U.S. subprime mortgage market — Fannie Mae and Freddie Mac. In October, the British Chancellor of the Exchequer referred to Keynes as he announced plans for substantial fiscal stimulus to head off the worst effects of recession, in accordance with Keynesian economic thought. Similar policies have been adopted by other governments worldwide. This is in stark contrast to the action permitted to Indonesia during its financial crisis of 1997, when it was forced by the IMF to close 16 banks at the same time, prompting a bank run. Much of the recent discussion reflected Keynes's advocacy of international coordination of fiscal or monetary stimulus, and of international economic institutions such as the International Monetary Fund and the World Bank, which many had argued should be reformed at a "new Bretton Woods" even before the crises broke out. IMF and United Nations economists advocated a coordinated international approach to fiscal stimulus. Donald Markwel argued that in the absence of such an international approach, there would be a risk of worsening international relations and possibly even world war arising from similar economic factors to those present during the depression of the 1930s.

By the end of December 2008, the Financial Times reported that "the sudden resurgence of Keynesian policy is a stunning reversal of the orthodoxy of the past several decades" In December 2008, Paul Krugman released his book, The Return of Depression Economics and the Crisis of 2008, arguing that economic conditions similar to that which existed during the earlier part of the century had returned, making Keynesian policy prescriptions more relevant than ever. In February 2009 Shiller and George Akerlof published Animal Spirits, a book where they argue the current US stimulus package is too small as it does not take into account Keynes's insight on the importance of confidence and expectations in determining the future behaviour of businessmen and other economic agents. In a March 2009 speech entitled Reform the International Monetary System, Zhou Xiaochuan, the governor of the People's Bank of China came out in favour of Keynes's idea of a centrally managed global reserve currency. Dr Zhou argued that it was unfortunate that part of the reason for the Bretton Woods system breaking down was the failure to adopt Keynes's Bancor. Dr Zhou proposed a gradual move towards increased used of IMF Special Drawing Rights (SDRs). Although Dr Zhou's ideas have not yet been broadly accepted, leaders meeting in April at the 2009 G-20 London summit agreed to allow $250 Billion of Special Drawing Rights to be created by the IMF, to be distributed globally. Stimulus plans have been credited for contributing to a better than expected economic outlook by both the OECD and the IMF, in reports published in June and July 2009. Both organizations warned global leaders that recovery is likely to be slow, so counter recessionary measures ought not be rolled back too early.

While the need for stimulus measures has been broadly accepted among policy makers, there has been much debate over how to fund the spending. Some leaders and institutions such as Angela Merkel and the European Central Bank have expressed concern over the potential impact on inflation, national debt and the risk that a too large stimulus will create an unsustainable recovery. Among professional economists the revival of Keynesian economics has been even more divisive with over 300 economists signing a petition stating that they do not believe higher government spending will help the United States's economy and some senior figures such as Robert Lucas remaining skeptical whether stimulus packages can work at all.

Keynes's early romantic and sexual relationships were almost exclusively with men. Attitudes in the Bloomsbury Group, in which Keynes was avidly involved, were relaxed about homosexuality. One of his great loves was the artist Duncan Grant, whom he met in 1908, and he was also involved with the writer Lytton Strachey. Keynes was open about his homosexuality, and between 1901 to 1915, kept separate diaries in which he tabulated his sexual relationships. In 1921 he fell "very much in love" with Lydia Lopokova, a well-known Russian ballerina, and one of the stars of Serge Diaghilev's Ballets Russes. They married in 1925, leading to the widely repeated couplet of unknown authorship: "Oh what a marriage of beauty and brains. The fair Lopokova and John Maynard Keynes". Their union was by all accounts happy, though childless – Lydia became pregnant in 1927 but miscarried. For the first years of the relationship, Keynes had maintained an affair with a younger man, Sebastian Sprott, in tandem with Lopokova, but he eventually chose Lopokova exclusively on marrying her. Among Keynes' Bloomsbury friends, Lepokova was, at least initially, subjected to criticism for her manners, mode of conversation and supposedly humble social origins - the latter of the causes being particularly noted in the letters of Vanessa and Clive Bell, and Virginia Woolf. E.M. Forster would later write in contrition: 'How we all used to underestimate her'.

Keynes was ultimately a successful investor, building up a substantial private fortune. He was nearly wiped out following the Stock Market Crash of 1929 which he failed to foresee, but he soon recouped his fortune. At his death in 1946 Keynes's worth stood just short of £500,000 - equivalent to about £11 million ($16.5 million) in 2009. The sum had been amassed despite lavish support for various good causes and his personal ethics which made him reluctant to sell on a falling market as he knew if too many did that it could deepen a slump. Keynes built up a significant collection of fine art, including works by Paul Cézanne, Edgar Degas, Amadeo Modigliani, Georges Braque, Picasso, and Georges-Pierre Seurat. He enjoyed collecting books: for example, he collected and protected many of Isaac Newton's papers. It is in part on the basis of these papers that Keynes wrote of Newton as "the last alchemist." He was interested in literature in general and drama in particular and supported the Cambridge Arts Theatre financially, which allowed the institution, at least for a while, to become a major British stage outside of London. Like several other notable British authors of his time, Keynes was a member of the Bloomsbury Group. Keynes was a life-long member of the Liberal party, which until the 1920s had been one of the two main political parties in Great Britain, and as late as 1916 had often been the dominant power in government. Keynes had helped campaign for the Liberals at elections from as early as 1906, yet he always refused to run for office himself, despite being asked to do so on three separate occasions in 1920. From 1926 when Lloyd George became leader of the Liberals, Keynes took a major role in defining the party's economics policy, but by then the Liberals had been displaced into third party status by the Labour party. Keynes's personal interest in Classical Opera and Dance led him to support the Royal Opera House at Covent Garden and the Ballet Company at Sadler's Wells. During the War as a member of CEMA (Council for the Encouragement of Music and the Arts) Keynes helped secure government funds to maintain both companies while their venues were shut. Following the War Keynes was instrumental in establishing the Arts Council of Great Britain and was the founding Chairman in 1946. Unsurprisingly from the start the two organisations that received the largest grant from the new body were the Royal Opera House and Sadler's Wells. Keynes was a proponent of eugenics, having served as Director of the British Eugenics Society from 1937 to 1944. As late as 1946, before his death, Keynes declared eugenics to be "the most important, significant and, I would add, genuine branch of sociology which exists." Throughout his life Keynes worked energetically for the benefit both of the public and his friends – even when his health was poor he laboured to sort out the finances of his old college and to try to design an international monetary system that would benefit the whole world at Bretton Woods. Keynes suffered a series of heart attacks, which ultimately proved fatal, during negotiations for an Anglo-American loan in Savanna, Georgia, he was trying to secure on favourable terms for Great Britain from the United States, a process he described as "absolute hell". Keynes died of a heart attack at Tilton, his farmhouse home near Firle, East Sussex, on 21 April 1946 at age 62. It was a few weeks after returning from America. Both of Keynes's parents outlived him: father John Neville Keynes (1852–1949) by three years, and mother Florence Ada Keynes (1861–1958) by 12 years. Keynes's brother Sir Geoffrey Keynes (1887–1982) was a distinguished surgeon, scholar and bibliophile. His nephews include Richard Keynes (born 1919) a physiologist; and Quentin Keynes (1921–2003) an adventurer and bibliophile. His widow, Lydia Lopokova, lived on until 1981.