John Gibson of Fox News says that Karl Rove should be given a medal. I agree: Mr. Rove should receive a medal from the American Political Science Association for his pioneering discoveries about modern American politics. The medal can, if necessary, be delivered to his prison cell.

What Mr. Rove understood, long before the rest of us, is that we're not living in the America of the past, where even partisans sometimes changed their views when faced with the facts. Instead, we're living in a country in which there is no longer such a thing as nonpolitical truth. In particular, there are now few, if any, limits to what conservative politicians can get away with: the faithful will follow the twists and turns of the party line with a loyalty that would have pleased the Comintern.

I first realized that we were living in Karl Rove's America during the 2000 presidential campaign, when George W. Bush began saying things about Social Security privatization and tax cuts that were simply false. At first, I thought the Bush campaign was making a big mistake - that these blatant falsehoods would be condemned by prominent Republican politicians and Republican economists, especially those who had spent years building reputations as advocates of fiscal responsibility. In fact, with hardly any exceptions they lined up to praise Mr. Bush's proposals.

But the real demonstration that Mr. Rove understands American politics better than any pundit came after 9/11.

Every time I read a lament for the post-9/11 era of national unity, I wonder what people are talking about. On the issues I was watching, the Republicans' exploitation of the atrocity began while ground zero was still smoldering.

Mr. Rove has been much criticized for saying that liberals responded to the attack by wanting to offer the terrorists therapy - but what he said about conservatives, that they "saw the savagery of 9/11 and the attacks and prepared for war," is equally false. What many of them actually saw was a domestic political opportunity - and none more so than Mr. Rove.

A less insightful political strategist might have hesitated right after 9/11 before using it to cast the Democrats as weak on national security. After all, there were no facts to support that accusation.

But Mr. Rove understood that the facts were irrelevant. For one thing, he knew he could count on the administration's supporters to obediently accept a changing story line. Read the before-and-after columns by pro-administration pundits about Iraq: before the war they castigated the C.I.A. for understating the threat posed by Saddam's W.M.D.; after the war they castigated the C.I.A. for exaggerating the very same threat.

Mr. Rove also understands, better than anyone else in American politics, the power of smear tactics. Attacks on someone who contradicts the official line don't have to be true, or even plausible, to undermine that person's effectiveness. All they have to do is get a lot of media play, and they'll create the sense that there must be something wrong with the guy.

And now we know just how far he was willing to go with these smear tactics: as part of the effort to discredit Joseph Wilson IV, Mr. Rove leaked the fact that Mr. Wilson's wife worked for the C.I.A. I don't know whether Mr. Rove can be convicted of a crime, but there's no question that he damaged national security for partisan advantage. If a Democrat had done that, Republicans would call it treason.

But what we're getting, instead, is yet another impressive demonstration that these days, truth is political. One after another, prominent Republicans and conservative pundits have declared their allegiance to the party line. They haven't just gone along with the diversionary tactics, like the irrelevant questions about whether Mr. Rove used Valerie Wilson's name in identifying her (Robert Novak later identified her by her maiden name, Valerie Plame), or the false, easily refuted claim that Mr. Wilson lied about who sent him to Niger. They're now a chorus, praising Mr. Rove as a patriotic whistle-blower.

Ultimately, this isn't just about Mr. Rove. It's also about Mr. Bush, who has always known that his trusted political adviser - a disciple of the late Lee Atwater, whose smear tactics helped President Bush's father win the 1988 election - is a thug, and obviously made no attempt to find out if he was the leaker.

Most of all, it's about what has happened to America. How did our political system get to this point?