Pop culture sure moves quickly. Just last week, Paris Hilton was so 20 minutes ago. And John McCain was drawing snickers from pop culture aficionados for choosing her and another relative has-been, Britney Spears, in his attack ad against Barack Obama.

But now, with Hilton's cheeky video riposte to the McCain ad thrusting her back into our collective consciousness, she's current again.

And so the head spins: Does that mean John McCain is now cutting edge?

Maybe. One thing, though, is clear: Politicians have long used pop culture references to bring a little spark to their campaigns, and it's a risky business. When you hit it just right, it can work wonders. But you'd better make sure you're up to date. Otherwise, a campaign can be accused of being, well, so 20 minutes ago.

Which is what pop culture scholars and humorists have been saying about whoever dreamed up McCain's Paris-Britney ad, which, you'll recall, juxtaposed images of the two with footage of Obama feted by adoring crowds in Berlin, suggesting Obama's celebrity was of the same inconsequential nature.

Paris Hilton and Britney Spears? "Circa 2003!" quipped Daniel Kurtzman, editor of the about.com political humor page. Marty Kaplan, a media analyst and a former Democratic speechwriter, imagined the ad had been dreamed up "by some aging boomer at the campaign, late at night, surrounded by old issues of People."

Political satirist Andy Borowitz, meanwhile, could only note that this was the same candidate who calls his opponent "Dr. No" _ a reference to Obama's response to McCain's energy proposals. "A 1962 James Bond movie _ the kids today oughtta love that!"

In seriousness, many have pointed out that McCain's ad, and a second one using Charlton Heston's Moses to mock Obama's soaring rhetoric, amount to a clever trick: turning what are some of Obama's greatest strengths into negatives.

And whether the presumed Republican nominee will benefit in the polls, he's certainly gotten attention. The Project for Excellence in Journalism, which measures media coverage of the candidates, said he managed to virtually tie Obama in press attention the week of July 28-Aug. 3, for the first time since the kickoff of the general election.

But the Spears-Hilton ad, especially, has been roundly criticized for being either unfair, illogical or trivial, and not just by those with Democratic leanings. John Weaver _ a former top McCain aide, now estranged from the candidate _ has publicly called it "childish" and said: "This tomfoolery needs to stop."

Hilton, though, was game for a little tomfoolery herself.

In her video, posted on the comedy site Funny or Die, the doe-eyed hotel heiress says, "Hey America, I'm Paris Hilton, and I'm a celebrity, too." Since that "wrinkly white-haired guy" put her in one of his ads, she says, lounging in a leopard-print swimsuit with keyhole cutouts and metallic pumps, "I guess that means I'm running for president." She fuses McCain's and Obama's energy talking points into her own succinct hybrid proposal, then announces she's off to find a VP.

Not that she had the last word. "Paris Hilton might not be as big a celebrity as Barack Obama, but she obviously has a better energy plan," said McCain spokesman Tucker Bounds.

All this back-and-forth between a socialite most famous for a jail term and a sex video and the man who might be president could seem, to some, a dangerous blurring of the lines between pop culture and politics. But those who study such things say these lines have long been blurred.

"What we produce in this country more than anything is pop culture," said Todd Boyd, professor of popular culture at USC. It's natural, he said, that the two worlds sometimes merge.

Pop culture references in campaigns haven't always involved celebrities. Walter Mondale in a 1984 debate took the inventive step of channeling a well-known commercial. Of rival Democrat Gary Hart's policies, he asked: "Where's the beef?" It was, of course, the slogan of the classic Wendy's ad. Continued...