Political parties are in bad odor these days. Although Arnold Schwarzenegger ran as a Republican, he appointed a cabinet that is safely bipartisan. Even his marriage is bipartisan. During President Clinton’s impeachment, Schwarzenegger declared that he was ashamed to be a Republican—though it is deliciously unclear whether his embarrassment was because of the G.O.P.’s excesses or his own, since revealed and regretted.

At any rate, his ambivalence is hardly unique. In 2000, George W. Bush ran for office proclaiming that he was “a uniter, not a divider.” He prescribed “compassionate conservatism”—a phrase, as David Frum pointed out, that combines the Left’s favorite adjective with the Right’s favorite noun—in order to transcend the country’s tired old divisions between Left and Right. Bill Clinton urged us to “move on” long before he lied to us about not lying to us. In 1992 and 1996, he championed the “Third Way” as the “bridge to the 21st century” that would soar over the muddy trenches of liberalism and conservatism.

Old-fashioned bipartisanship, notably the anti-Communist consensus that dominated American foreign policy from the end of the Second World War to the Vietnam War, had its problems. We tend to forget the pitched battles over who lost China or what to do in Korea. Nonetheless, the consensus was rough but real, and it held for a generation or more. It depended on anti-Communist principles that were widely shared and deeply felt. Today’s bipartisanship, by contrast, appeals to notions widely shared but not at all deeply felt (faith-based initiatives), to policies deeply felt but not at all widely shared (school vouchers), or to initiatives whose very popularity bespeaks their political triviality (school uniforms).

The new bipartisanship, in short, is rather a dream than a reality. It depends on trying to downsize political issues, as though consensus could be built by ignoring all the more urgent and important conflicts. When that proves untenable or ridiculous, as it must, then our eager bipartisans look forward hopefully to the emergence of a new consensus. Now, it’s one thing to subordinate, or postpone, disagreements in favor of a more fundamental agreement. It’s quite another to try this in the future tense, on behalf of a prophecy.

In other words, the bipartisan wish is father to the thought. Instead of organizing a real majority around real issues, our bipartisans embrace a theoretical majority that is supposed to organize itself in accordance with the spirit of a new age. Because neither liberalism nor conservatism has triumphed, they conclude that both have lost and that the future belongs to their synthesis, which will emerge because it’s the only thing left to emerge. They expect a consensus without conflicts, a reasonable outcome without anyone’s reason to guide it.

But pseudo-bipartisanship never works out. It evaporates quickly, like the morning fog on a battlefield. When Bush was in trouble in the early primaries, he moved sharply rightward against Senator John McCain; in the general election, Bush attacked Vice President Gore as lustily as Ronald Reagan ever flogged the hapless Walter Mondale, and on much the same grounds: that the Democrat stood for Big Government. Gore returned the compliment, noting Bush’s affinity to the notorious Social Darwinists (the only kind of Darwinist that Democrats are allowed to dislike). After all the 1990s’ talk of moving beyond the old divisions, the decade ended in the bitter 2000 election, with a country that was bipartisan, all right—evenly split down the middle between two rancorous parties.

When the bipartisan high fades, it leaves a nasty hangover. In the first place, it raises voters’ expectations, only to dash them. Why can’t we all just get along? The question demands an answer, and many voters conclude that both parties must somehow be to blame, which isn’t unreasonable. After all, if party leaders (who should know) rail against partisanship, surely it follows that there must be something wrong with partisanship. The suspicion grows that neither party can speak for the whole country and that each is, in James Madison’s terms, a faction, composed of careerists or extremists or both, but not of anyone you’d like to think of as your representative. Hard-core partisans, of course, draw quite a different conclusion from bipartisanship’s failure. It teaches them what they already knew, that the other party cannot be trusted.

Perhaps a little humility is in order: politics means disagreement, and no amount of enlightenment or good will can abolish that. Self-government proceeds by constitutional majorities, which are usually forged first by dividing, and then by uniting, the public. Expecting political conflict, politicians and citizens alike might take more seriously the responsibility to choose between partisan opinions of the common good, because no one else, least of all the elusive bipartisans, is going to do it for them.