New York Times columnist Nick Kristof is bemoaning the foaming-at-the-mouth hatred that dominates partisan debate in today's America. "I'm afraid that America is now transforming into.....the political moonscape that I remember when I was a student in England in the 1980's," he writes. "Left and right came from different social classes, lived in different areas, attended different schools and despised each other." Andrew Sullivan has similar thoughts.

Kristof and Sullivan should stop worrying so much. The bitter rancor that typifies the current left-right divide in the US is a cyclical phenomenon, riding on the confluence of a trio of polarizing factors that will inevitably dissipate:

Political change. The decade of the 1980's in Britain was the Margaret Thatcher era, when the dominance of welfare state politics was being challenged by the rise of a new free enterprise-oriented middle class. Like all momentous changes, that one brought the conflicting interests of rival political coalitions into stark contrast, as old compromises became irrelevant and new ones had yet to be stricken. The sharp rightward shift in American politics in the post-Clinton era has shaken things up here in similar fashion, and the scrambling over suddenly up-for-grabs assets (the fealty of the judiciary, for instance) is bound to get somewhat testy.

Momentous issues It would be nice if partisan debate over the war on terror could be polite and genteel. Unfortunately, the issue is of such obviously enormous importance that disagreements about it seem petty unless they are themselves claimed to be of deep and monumental importance. There's no point whatsoever in carping about the details of homeland security or the war in Iraq--if there's any disagreement at all, it must be asserted that it is the nation's very safety--perhaps even survival--that is at stake. Such circumstances don't exactly encourage restrained rhetoric.

A polarizing leader. it's hard to imagine a more polarizing figure than Margaret Thatcher, the "Iron Lady" who ruled her party absolutely and came to embody everything her party, faction and constituency stood for. Likewise, Bill Clinton, a president facing (after 1994) a House and Senate united against him, became, in effect, the sole major national political figure to represent his half of the electorate. And George W. Bush, because of the dominance of the presidency in the suddenly-crucial foreign policy arena (and partly because of a leadership vaccuum in Congress these days, especially on the Republican side) has found himself with an almost Clintonian level of pre-eminence when compared with any of his political allies. Needless to say, all three of these politicians were passionately adored and embraced by their "own" side--and intensely hated and excoriated by their opponents.

Of course, these three factors tend to decline with time, as political waves of change peter out, as the intensity of major crises dissipates, and as dominant leaders eventually lose their aura of invincibility and are shunted aside. As Kristof notes, "Europe has matured and become much less polarized" since his time there. There's no reason not to expect a similar outcome here, in due time.