Four years into a war fought to eliminate a nonexistent threat, we all have renewed appreciation for the power of the Big Lie: people tend to believe false official claims about big issues, because they can't picture their leaders being dishonest about such things.
But there's another political lesson I don't think has sunk in: the power of the Little Lie - the small accusation invented out of thin air, followed by another, and another, and another. Little Lies aren't meant to have staying power. Instead, they create a sort of background hum, a sense that the person facing all these accusations must have done something wrong.
For a long time, basically from 9/11 until the last remnants of President Bush's credibility drowned in New Orleans, the Bush administration was able to go big on its deceptions. Most people found it inconceivable that an American president would, for example, assert without evidence that Saddam and Al Qaeda were allies. Mr. Bush won the 2004 election because a quorum of voters still couldn't believe he would grossly mislead them on matters of national security.
Before 9/11, however, the right-wing noise machine mainly relied on little lies. And now it has returned to its roots.
The Clinton years were a parade of fake scandals: Whitewater, Troopergate, Travelgate, Filegate, Christmas-card-gate. At the end, there were false claims that Clinton staff members trashed the White House on their way out.
Each pseudoscandal got headlines, air time and finger-wagging from the talking heads. The eventual discovery in each case that there was no there there, if reported at all, received far less attention. The effect was to make an administration that was, in fact, pretty honest and well run - especially compared with its successor - seem mired in scandal.
Even in the post-9/11 environment, little lies never went away. In particular, promoting little lies seems to have been one of the main things U.S. attorneys, as loyal Bushies, were expected to do. For example, David Iglesias, the U.S. Attorney in New Mexico, appears to have been fired because he wouldn't bring unwarranted charges of voter fraud.
There's a lot of talk now about a case in Wisconsin, where the Bush-appointed U.S. attorney prosecuted the state's purchasing supervisor over charges that a court recently dismissed after just 26 minutes of oral testimony, with one judge calling the evidence "beyond thin." But by then the accusations had done their job: the unjustly accused official had served almost four months in prison, and the case figured prominently in attack ads alleging corruption in the Democratic governor's administration.
This is the context in which you need to see the wild swings Republicans have been taking at Nancy Pelosi.
First, there were claims that the speaker of the House had demanded a lavish plane for her trips back to California. One Republican leader denounced her "arrogance of extravagance" - then, when it became clear that the whole story was bogus, admitted that he had never had any evidence.
Now there's Ms. Pelosi's fact-finding trip to Syria, which Dick Cheney denounced as "bad behavior" - unlike the visit to Syria by three Republican congressmen a few days earlier, or Newt Gingrich's trip to China when he was speaker.
Ms. Pelosi has responded coolly, dismissing the administration's reaction as a "tantrum." But it's more than that: the hysterical reaction to her trip is part of a political strategy, aided and abetted by news organizations that give little lies their time in the sun.
Fox News, which is a partisan operation in all but name, plays a crucial role in the Little Lie strategy - which is why there is growing pressure on Democratic politicians not to do anything, like participating in Fox-hosted debates, that helps Fox impersonate a legitimate news organization.
But Fox has had plenty of help. Even Time's Joe Klein, a media insider if anyone is, wrote of the Pelosi trip that "the media coverage of this on CNN and elsewhere has been abysmal." For example, CNN ran a segment about Ms. Pelosi's trip titled "Talking to Terrorists."
The G.O.P.'s reversion to the Little Lie technique is a symptom of political weakness, of a party reduced to trivial smears because it has nothing else to offer. But the technique will remain effective - and the U.S. political scene will remain ugly - as long as many people in the news media keep playing along.
I appreciate Krugman's conclusion: that none of this could be done - at least not so effectively - if the mainstream media were not in the Republicans' pocket.