Republican presidential candidate John McCain, once renowned for his jocular sessions with journalists, appeared irritable and at times sarcastic in an interview in which he defended running mate Sarah Palin’s experience and campaign ads critical of rival Barack Obama.

Meeting Tuesday with the editorial board of The Des Moines Register, McCain was asked why he picked the Alaska governor, someone “who doesn’t have a lot of experience.”

“Thank you, but I disagree with your fundamental principle that she doesn’t have the experience,” McCain replied before citing Palin’s work as a PTA member, city council member, mayor and governor. “You and I just have a fundamental disagreement, and I am so happy the American people seem to be siding with me.”

When it was suggested that Palin’s lack of experience worried voters, McCain turned sarcastic.

“Really? I haven’t detected that in the polls, I haven’t detected that among the base,” he said. “If there’s a Georgetown cocktail party person who, quote, calls himself a conservative who doesn’t like her, good luck. I don’t dismiss him. I think the American people have overwhelmingly shown their approval.”

Obama spokesman Hari Sevugan dismissed the session as a “sarcastic diatribe” that indicated McCain wouldn’t change the atmosphere in Washington. “John McCain offered nothing more than snide, frustrated responses,” Sevugan said.

At another point, McCain was asked if he’s strayed from his “straight talk” image with advertising that some have labeled deceptive. McCain dryly responded, “It would be valuable if you gave some examples for an assertion of that nature.”

He went on to say: “I have always had 100 percent, absolute truth, that’s been my life and putting my country first. I’ll match that record with anyone and an assertion that I have ever done otherwise, I take strong exception to.”

As examples, a questioner at the Register noted a McCain commercial that suggested Obama favored comprehensive sex education for kindergartners and assertions by his campaign that a “lipstick on a pig” comment Obama made was a reference to Palin. News media fact-checking the sex education ad deemed it deceptive and a distortion of Obama’s position.

“It certainly is your opinion and I respect your opinion, but it’s not the facts,” McCain said in the interview. “I respect your opinion. I strongly disagree with your assertion.”

He also sarcastically referred to his five years as a prisoner of war when answering a question about his having government-financed health care throughout his military and congressional career.

“The answer is that most of my life, in serving my country, I have had health care,” he said. “I did go for a period of time when the health care wasn’t very good.”

McCain met privately with the newspaper’s editorial board after holding an economic roundtable earlier in the day at a Des Moines business. The newspaper posted videos of the session on its Web site.