One of the most extraordinary features of Barack Obama's victory over John McCain was his capture of 78% of the Jewish vote. To be sure, there was nothing extraordinary about the number itself. Since 1928, the average Jewish vote for the Democrat in presidential elections has been an amazing 75%—far higher than that of any other ethno-religious group.

Yet there were reasons to think that it would be different in 2008. The main one was Israel. Despite some slippage in concern for Israel among American Jews, most of them were still telling pollsters that their votes would be strongly influenced by the positions of the two candidates on the Jewish state. This being the case, Mr. McCain's long history of sympathy with Israel should have given him a distinct advantage over Mr. Obama, whose own history consisted of associating with outright enemies of the Jewish state like the Rev. Jeremiah Wright and the historian Rashid Khalidi.

Nevertheless, Mr. Obama beat Mr. McCain among Jewish voters by a staggering 57 points. Except for African Americans, who gave him 95% of their vote, Mr. Obama did far better with Jews than with any other ethnic or religious group. Thus the Jewish vote for him was 25 points higher than the 53% he scored with the electorate as a whole; 35 points higher than the 43% he scored with whites; 11 points higher than the 67% he scored with Hispanics; 33 points higher than the 45% he scored with Protestants; and 24 points higher than the 54% he scored with Catholics.

These numbers remind us of the extent to which the continued Jewish commitment to the Democratic Party has become an anomaly. All the other ethno-religious groups that, like the Jews, formed part of the coalition forged by Franklin Delano Roosevelt in the 1930s have followed the rule that increasing prosperity generally leads to an increasing identification with the Republican Party. But not the Jews. As the late Jewish scholar Milton Himmelfarb said in the 1950s: "Jews earn like Episcopalians"—then the most prosperous minority group in America—"and vote like Puerto Ricans," who were then the poorest.

Jews also remain far more heavily committed to the liberal agenda than any of their old ethno-religious New Deal partners. As the eminent sociologist Nathan Glazer has put it, "whatever the promptings of their economic interests," Jews have consistently supported "increased government spending, expanded benefits to the poor and lower classes, greater regulations on business, and the power of organized labor."