KENNEBUNKPORT, Maine – Republican John McCain worked on Monday to wrestle the spotlight from rival Barack Obama's tour of Iraq by insisting he was right and the Democrat was wrong about the war and releasing a new critical ad blaming higher gas prices on his opponent.

As Obama toured the war zones trailed by U.S. network TV anchors, McCain ridiculed him from afar during a visit with the first President George Bush at his summer home on the Atlantic. At the same time, the Republican contender released an eyebrow-raising new ad flatly blaming the Illinois senator for higher gasoline prices.

The Republican and Democratic presidential contenders have differed sharply over Iraq. Obama has said he would withdraw U.S. troops from combat there over 16 months while reinforcing the U.S. effort against al-Qaeda and the Taliban in Afghanistan. McCain has resisted any timetable for withdrawal, insisting that victory in Iraq is a necessary precursor to success in Afghanistan.

Any withdrawal of troops from Iraq “must be based on conditions on the ground,” McCain told reporters as he stood beside the 84-year-old former president.

The Arizona senator disparaged Obama as “someone who has no military experience whatsoever.”

“When you win wars, troops come home,” McCain said. “He's been completely wrong on the issue. ... I have been steadfast in my position.”

On Afghanistan, McCain said, “I've always said it's long and tough and hard.”

As to Iraq, “We've succeeded. We're not succeeding, we've succeeded,” McCain said later at a fundraiser.

McCain told reporters he didn't care if Obama's trip was stealing attention and “doesn't in the slightest undercut” his own message.

Stewart Iverson, chairman of Iowa's Republican Party, said he's hopes voters will conclude from Obama's overseas visit that “one trip doesn't make you an expert in foreign policy.”

He said the McCain campaign will have to keep pointing out the differences between the candidates' stances on foreign policy. “It's not something that you do in one speech. It's not just today and tomorrow. It's next week, it's next month,” he said.

Iverson predicted the foreign trip may provide “a bump for a little bit for Obama.” But as for a lasting impact on McCain, he said, “I don't think necessarily it's going to hurt him.”

The elder Bush declined to advise McCain on the two wars, noting that he no longer follows every headline each day.

“No advice,” Bush said. “My respect for him knows no bounds.”

Bush would not criticize either McCain for advocating oil drilling on the Outer Continental Shelf nor his son for rescinding his own 1992 presidential order banning such offshore drilling. Increasing domestic production was important, Bush said.

In a TV ad on national cable and in 11 states, McCain pushed his support for offshore drilling as the remedy for rising gas prices.

And even though McCain opposes drilling in the Arctic National Wildlife Refuge in Alaska and during his 2000 presidential run opposed lifting the offshore drilling moratorium, his ad clearly tries to blame rising prices on support for the moratorium by Obama, a first-term Illinois senator.

As the price readout on a lonely gas pump rolls over to $5, the announcer asks, “Who can you thank for rising prices at the pump?” Rising from the background is the sound of a crowd chanting: “Obama, Obama, Obama.” A smiling Obama appears on the screen with a pump rising over his right shoulder.

Finally the announcer says: “One man knows we must now drill more in America and rescue our family budgets. Don't hope for more energy, vote for it. McCain.”

This ad is the latest tit-for-tat commercial over energy in the presidential campaign. Earlier this month, an Obama ad accused McCain of being “part of the problem” of high gas prices.

The main premise of McCain's ad – that opposition to drilling is responsible for high gas prices – is disputed even by McCain allies. In arguing for an end to the offshore moratorium and for drilling in the Alaska preserve, President Bush said that these steps “will take years to have their full impact” on energy costs.