WASHINGTON: Democratic presidential contender Sen. Barack Obama stepped off the campaign trail and into the Hawaiian surf last weekend, joking, “I’m going to go body surfing at an undisclosed location” — referring to former Sen. John Kerry’s disastrous body surfing photo that some say cost him the presidential ticket four years ago.

Obama may be on vacation, but there is no holiday from the relentless attacks of his GOP rival, Sen. John McCain.

The Republican this week intensified his assault, saying with victory in sight, the hard-won gains of Iraq would be lost under his Democratic rival.

“The lasting advantage of a peaceful and democratic ally in the heart of the Middle East could still be squandered by hasty withdrawal and arbitrary timelines,” McCain said in Las Vegas. “And this is one of many problems in the shifting positions of my opponent, Sen. Obama.”

McCain stepped up the pressure with three new attack ads, one of which concluded, “Not ready to lead. That’s the real Obama.”

Obama clearly wasn’t amused when, two weeks ago, McCain’s campaign tried to turn his big crowd advantage into a liability — casting him as the “biggest celebrity in the world” in an ad that interspersed images of the Democratic candidate speaking to thousands in Berlin with paparazzi-style shots of Paris Hilton and Britney Spears.

McCain’s campaign was trying to persuade voters that Obama wasn’t ready for the presidency.

Now, nearly two weeks later, Obama’s campaign is offering its counterpunch: a cable TV ad slapping McCain with the less glamorous label of “Washington’s biggest celebrity.”

The ad shows the Arizona senator gabbing with the ladies on late night television talk shows, plus six photos of McCain with President Bush, including one of McCain hugging Bush as the announcer intones, “As Washington embraced him, John McCain hugged right back.”

Then there’s a slow-motion shot of McCain walking with a group that the announcer identifies as “the lobbyists running his low-road campaign.”

“A Washington celebrity playing the same old Washington games,” the ad concludes.

As the 2008 presidential race gets closer to the November elections, the more the advertising will be ratcheted up — by both of the campaigns and the myriad independent groups sure to emerge.

But what about the issues? While the stumbling American economy is the prime issue in the 2008 campaign, McCain has routinely sought to play on his long association with international and security affairs against Obama’s short record on the national stage.

The two are most at odds over Iraq, where Obama opposed the war before it began and now wants to withdraw American forces within 16 months of taking office, should he win. McCain supported the war and the so-called surge that has been credited with bringing down violence. McCain says US troops should remain in Iraq until “conditions on the country” allow a withdrawal, even if it takes “a hundred years.”

On the running dispute between McCain and Obama on the other key foreign affairs issue facing voters this year, McCain portrayed Obama as focused more on his own ambition than military success in Iraq.

Obama argued that McCain favors extending a war that is hurting Americans at home.

Meanwhile, Obama campaign has announced that Hillary Rodham Clinton will speak on Aug. 26 at the party’s Denver convention.