"He really has no experience or knowledge or judgment about the issue of Iraq and he has wanted to surrender for a long time," the Arizona senator added. "If there was any other issue before the American people, and you hadn't had anything to do with it in a couple of years, I think the American people would judge that very harshly."
McCain, a Navy veteran and Vietnam prisoner of war, frequently argues that he's the most qualified candidate to be a wartime commander in chief. In recent weeks, he has sought portray Obama, a first-term senator, as naive on foreign policy and not experienced enough to lead the military.
The Iraq war, which polls have shown that most of the country opposes, is shaping up to be a defining issue in the November presidential election.
McCain, who wrapped up the GOP nomination in March, supports continued military presence in Iraq though he recently said he envisions victory with most U.S. troops coming home by January 2013 if he's elected. Obama, who has all but clinched the Democratic nomination, says he will remove U.S. combat troops within 16 months of taking office, though sometimes he shortens it to 11 months.
"For him to talk about dates for withdrawal, which basically is surrender in Iraq after we're succeeding so well is, I think, really inexcusable," said McCain, who has been to Iraq eight times, most recently in March.
Obama spokesman Bill Burton declined to respond directly to McCain, saying only: "Senator Obama thinks Memorial Day is a day to honor our nation's veterans, not a day for political posturing."
Over the weekend, Sen. Lindsey Graham, one of McCain's top surrogates, laid the groundwork for McCain's criticism in a television interview in which he noted Obama's absence from Iraq and floated the idea that Obama and McCain should go together to be briefed by Gen. David Petraeus, the top U.S. commander in Iraq, and Iraqi Prime Minister Nouri al-Maliki.
Asked whether he'd be willing to take such a trip, McCain told the AP: "Sure. It would be fine."
"I go back every few months because things are changing in Iraq," he said. McCain questioned whether Obama has ever been briefed by Petraeus. "I would also seize that opportunity to educate Senator Obama along the way."
Both McCain and Obama spent part of Memorial Day in New Mexico, a general election battleground that was decided by razor-thin margins in 2000, for Democrat Al Gore, and in 2004, for Republican President Bush.
Obama addressed veterans Monday in Las Cruces while McCain used a speech at the New Mexico Veterans Memorial in Albuquerque to press his case against withdrawing troops from Iraq, saying they must continue their mission even though he's "sick at heart" by mistakes at the outset of the war.
McCain also defended his opposition to Senate-passed legislation that would provide additional college financial aid to veterans, a measure Obama supports.
The Republican made no direct mention of the Democrat but seemed to poke at him nonetheless.
McCain said his opposition to the bill was the right rather than the politically expedient position, suggesting Obama was on the wrong side of the measure sponsored by Democratic Sen. Jim Webb of Virginia and approved by the Democratic-controlled Senate.
Lawmakers blocked a more limited version that McCain supported.
"I am running for the office of commander in chief. That is the highest privilege in this country, and it imposes the greatest responsibilities. And this is why I am committed to our bill, despite the support Senator Webb's bill has received," McCain said. "It would be easier, much easier politically for me to have joined Senator Webb in offering his legislation."
However, McCain said he opposed Webb's measure because it would give everyone the same benefit regardless of how many times they enlist. He said he feared that would depress reenlistments by those wanting to attend college after only a few years in uniform.
Rather, McCain said the bill he favored would have increased scholarships based on length of service.
McCain spent the early part of the holiday weekend at his retreat in Sedona, Ariz., where he entertained some two dozen guests, including three fellow Republicans who have been mentioned as possible vice presidential running mates: Florida Gov. Charlie Crist, Louisiana Gov. Bobby Jindal and former Massachusetts Gov.
Mitt Romney.
"It really was just a social occasion," McCain told the AP.
Asked whether he did any vetting of the three, McCain said: "None.
Zero. There is plenty of time for that kind of thing."
