NEW YORK — 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.

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 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, "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.

Arguably the most famous pop culture reference in a campaign — exquisite in its succinctness — was Richard Nixon's 1968 four-word appearance on "Rowan and Martin's Laugh-In," intoning the show's catch phrase, "Sock it to me?" (Nixon added the question mark.)

By 1992, candidate Bill Clinton knew how valuable it would be to play the saxophone on "The Arsenio Hall Show." And these days, it's a virtual rite of passage for candidates to appear on the late-night shows.

They don't simply chat. They duly appear in "Saturday Night Live" skits, read out David Letterman's often humiliating Top Ten lists, or suffer partisan questioning, in McCain's case, from "Daily Show" host Jon Stewart.

Why do the candidates endure this? It's free attention and self-deprecating humor endears them to an audience.

But when a politician veers into the attack mode of humor, it's more controversial. "When you get into mockery, that's where you potentially do more harm than good," Kurtzman, of about.com, noted.