That something is the unhinging of the Democratic Party. Democrats are seized with a loathing for President Bush � a contempt and disdain giving way to a hatred that is near pathological � unlike any since they had Richard Nixon to kick around. An otherwise reasonable man, Julian Bond of the N.A.A.C.P., speaks of Bush's staffing his Administration with "the Taliban wing of American politics." Harold Meyerson, editor at large of The American Prospect, devotes a 3,000-word article to explaining why Bush is the most dangerous President in all of American history � his only rival being Jefferson Davis.

The puzzle is where this depth of feeling comes from. Bush's manner is not particularly aggressive. He has been involved in no great scandals, Watergate or otherwise. He is, indeed, not the kind of politician who radiates heat. Yet his every word and gesture generate heat � a fury and bitterness that animate the Democratic primary electorate and explain precisely why Howard Dean has had such an explosive rise. More than any other candidate, Dean has understood the depth of this primal anti-Bush feeling and has tapped into it.

Whence the anger? It begins of course with the "stolen" election of 2000 and the perception of Bush's illegitimacy. But that is only half the story. An illegitimate President winning a stolen election would be tolerable if he were just a figurehead, a placeholder, the kind of weak, moderate Republican that Democrats (and indeed many Republicans) thought George Bush would be, judging from his undistinguished record and tepid 2000 campaign. Bush's great crime is that he is the illegitimate President who became consequential � revolutionizing American foreign policy, reshaping economic policy and dominating the political scene ever since his emergence as the post-9/11 war President.

Before that, Bush could be written off as an accident, a transitional figure, a kind of four-year Gerald Ford. And then came 9/11. Bush took charge, declared war, and sent the country into battle twice, each time bringing down enemy regimes with stunning swiftness. In Afghanistan, Bush rode a popular tide; Iraq, however, was a singular act of presidential will.

That will, like it or not, has remade American foreign policy. The Bush Revolution in Foreign Policy is the subtitle of a new book by two not very sympathetic scholars, Ivo Daalder and James Lindsay. The book is titled America Unbound. The story of the past two years could just as well be titled Bush Unbound. The President's unilateral assertion of U.S. power has redefined America's role in the world. Here was Bush breaking every liberal idol: the ABM Treaty, the Kyoto Protocol, deference to the U.N., subservience to the "international community." It was an astonishing performance that left the world reeling and the Democrats seething. The pretender had not just seized the throne. He was acting like a king. Nay, an emperor.

On the domestic front, more shock. Democrats understand that the Bush tax cuts make structural changes that will long outlive him. Like the Reagan cuts, they will starve the government of revenue for years to come. Add to that the Patriot Act and its (perceived) assault on fundamental American civil liberties, and Bush the Usurper becomes more than just consequential. He becomes demonic.

The current complaint is that Bush is a deceiver, misleading the country into a war, after which there turned out to be no weapons of mass destruction. But it is hard to credit the deception charge when every intelligence agency on the planet thought Iraq had these weapons and, indeed, when the weapons there still remain unaccounted for. Moreover, this is a post-facto rationale. Sure, the aftermath of the Iraq war has made it easier to frontally attack Bush. But the loathing long predates it. It started in Florida and has been deepening ever since Bush seized the post-9/11 moment to change the direction of the country and make himself a President of note.