Last year, at a campaign event in South Carolina, John McCain called on a woman who had a question about the expected Democratic nominee. "How do we beat the bitch?" she asked. McCain laughed, said, "That's an excellent question," and noted he was leading Clinton in a poll, before assuring his audience that "I respect Sen. Clinton."

Back then, sexism directed at a candidate for high office did not cause a wave of revulsion in McCain. But sometime in the last year, he had his consciousness raised. So when Barack Obama scoffed at the idea that the GOP ticket offered real change from President Bush, saying, "You can put lipstick on a pig -- it's still a pig," McCain's camp rose up in outrage at Obama for "comparing our vice presidential nominee, Gov. Palin, to a pig."

In this interpretation of Obama's remarks, the McCain people are -- what's the word I'm looking for? -- lying. They pretend to be unaware of the clear meaning of this old cliché, and the pretense is completely phony.

How can I be so sure? Last year, McCain said that Hillary Clinton's 2008 health-care plan was disturbingly similar to her 1993 version: "I think they put some lipstick on the pig, but it's still a pig." If that's a sly sexist insult, McCain owes Clinton a big apology.

Does anyone truly believe that Obama got up that morning trying to think of a sneaky way to call Sarah Palin a pig? Or that he is stupid enough to think he could get away with it? Is there anything in his past to suggest he talks or thinks about women in such terms? Of course not.

Now, politicians are not saints, and campaigns are not conducted under oath. We all expect a certain amount of deceit from people running for office, in the form of fudging, distortion, exaggeration and omission. But the McCain campaign's approach, as this episode illustrates, is of an entirely different scale and character. It is to normal political attacks what Hurricane Ike is to a drive-through car wash.

Take Palin's claim to have opposed the Bridge to Nowhere. Long after it was exposed as false, she kept making it. The assumption behind the McCain strategy is that truth is irrelevant.

Last week, he released a TV spot on education studded with falsehoods. It quoted the Chicago Tribune calling Obama a "staunch defender of the existing public school monopoly." But the Tribune didn't say it. I did, in a signed column in the Tribune, which praised McCain's support for school vouchers for low-income families.

The ad couldn't bother to explain why Obama is wrong about vouchers. Instead, it said his "one accomplishment" was a bill mandating sex education for kindergarteners. "Learning about sex before learning to read?" asked the narrator, implying that 5-year-olds would be taught the proper use of condoms before being taught their ABCs. Which, as it happens, is not true.

McCain may be the only candidate who has ever gotten in trouble with FactCheck.org for quoting FactCheck.org. Another commercial showed a photo of Obama while saying the group called the attacks on Palin "false" and "misleading." But the group quickly repudiated the charge.

The FactCheck article, it pointed out, "debunked a number of false or misleading claims that have circulated in chain e-mails and Internet postings regarding Palin." The ad, however, "strives to convey the message that FactCheck.org said 'completely false' attacks on Sarah Palin had come from Sen. Barack Obama. But we said no such thing. We have yet to dispute any claim from the Obama campaign about Palin."

Why does McCain insist on running such a mendacious campaign? There is plenty an honest conservative might say in opposition to Obama: He's wrong about Iraq. He's wrong about Iran. He's wrong about offshore oil drilling. He wants to raise taxes. He favors abortion on demand. He would appoint liberal judges. He would impede school reform.

But McCain has concluded that a fact-based case about Obama isn't enough to prevail in November. So he has chosen to smear his opponent with ridiculous claims that he thinks the American people are gullible enough to believe.

He has charged repeatedly that his opponent is willing to lose a war to win an election. What's McCain willing to lose to become president? Nothing so consequential as a war. Just his soul.

Steve Chapman's column is distributed by Creators Syndicate.