Mr Lipset, who died last week, started his academic career as a triple outsider—working-class, Jewish and left-wing in an academic world that was then still an extension of the WASP establishment. His parents were immigrants from tsarist Russia (his father once met Stalin). He attended the lowly City College of New York rather than Yale or one of the other Ivies. He became the national chairman of the Young People's Socialist League.

His youthful socialism provided him with his first problem of “American exceptionalism”: why is America the only industrial country that has never produced a major socialist party? Mr Lipset's first answer to the question emphasised the nature of the political system. Presidential elections discourage Americans from wasting their votes on a third-party candidate. And the loose structure of American parties encourages factions to work inside them, rather than outside.

Mr Lipset subsequently decided that he was wrong. A succession of third-party candidates—Theodore Roosevelt in 1912, George Wallace in 1968 and Ross Perot in 1992—have done respectably. The problem with socialist candidates is not that they are third-party candidates but that they are socialists.

He flirted with another explanation—that America has much higher degrees of social mobility than the socialist-breeding countries of Europe. But the data told a different story. Rates of social mobility were much the same in America and Europe. The big difference was in values. Americans believed strongly in equality of opportunity and equality of status. Europeans were still hung up on status differences—sometimes even using different words to address people of different ranks.

The question of America's unique values became increasingly central to his work. He also broadened his inquiry to American exceptionalism in general. Why does the United States have sky-high levels of religiosity? Why do Americans hate turning out to vote but love forming voluntary associations?

He emphasised America's hostility to the state—a hostility so strong that it even affected the left. The American Federation of Labour was significantly more militant than most European unions. But it had little truck with statism: its leader for almost four decades, Samuel Gompers, claimed that his politics were “two-thirds anarchist”. Today's defining left-wing issue is “choice”—that is, preventing the government from interfering with women's control over their own bodies.

He also emphasised America's tradition of assimilation. Mr Lipset argued that the tone of the country was set by George Washington, who once wrote to a synagogue stating that Jews were not “tolerated” in America: they were Americans. Mr Lipset noted that America had relatively high rates of marriage between Jews and gentiles and between other religious groups. “The melting pot is melting as never before,” he remarked in 1996, when other intellectuals were fixated on divisions.
Not much like Canada

Mr Lipset traced much of this American exceptionalism to 1776. The revolution not only got rid of feudalism. It also shattered the “confessional state”, creating a free market in religion. He loved to analyse the way in which the monarchist counter-revolution in Canada produced a very different society—much more deferential, communitarian and statist. The American and Canadian governments tried to introduce the metric system at almost the same time. Today the Canadians slavishly follow the metric system—and the Americans cheerfully continue in their old ways.

American exceptionalism, Mr Lipset admitted, was a “double-edged sword”. America is much better than Europe in some ways and much worse in others: more open and dynamic, but also more violent, crime-prone and unequal. America's virtues and vices are part and parcel of each other. Its commitment to meritocracy explains both its dynamism and its harshness towards failure. Its moralism explains both its reforming zeal and its suffocating self-righteousness.

Mr Lipset has few natural successors, not least because the melting pot is so good at turning outsiders into insiders. Most Americans instinctively regard America as the measure of all things. And the fashion for multiculturalism is paradoxically reinforcing this myopia; other countries are wonderful so long as they accept basic American values.

This is a pity. American exceptionalism is flourishing these days, after a brief retreat in the 1960s and 1970s. Hence the growing differences with Europe over everything from military intervention to capitalism. Many people are predicting a great coming together of Europe and America once George Bush leaves office. There will certainly be a good deal of making up for a while. But anybody who expects the pleasantries to last forever should read Seymour Martin Lipset.