Imagine a pair of bubble-headed teenage girls plunked down in the middle of "All the President's Men," then transform the major Watergate players (Nixon, Woodward, Bernstein, Liddy, et al) into oafs, and you have the recipe for "Dick," a nimbly-witted marriage of teenage social slapstick and political satire.

A cross-generational comedy that quickly lays out historical details for the uninitiated, then sets about clowning with the fuzzier facts, the movie stars Kirsten Dunst and Michelle Williams as a couple of dim and giggly 15-year-olds who stumble onto the Watergate break-in (one of them lives in the hotel), then become witnesses to President Nixon's cover-up, after being spotted on a White House tour and appointed "official White House dog-walkers" in order to keep them close and find out what they know.

Since their lives revolve around lip gloss and Bobby Sherman, it takes these two ditzes a while to catch on. After getting lost in the executive mansion, their new buddy President Nixon (a perfectly cast Dan Hedaya) plays off the document-shredding they've seen as a crafts project. "Paper mache is a hobby of mine," he grunts, momentarily unfurrowing his brow.

Then he asks them to be his "secret youth advisers," with the caveat that they can't talk about anything they witness in the White House. Star-struck Arlene (Williams) even develops a crush on Tricky Dick, leading to many obvious jokes that play off the double entendre of that particular first name.

But after finding a tape recorder in Dick's desk and recording an 18-and-a-half minute declaration of love to him, the girls rewind too far and hear Nixon swearing, lying and -- gasp! -- being mean to his dog. That does it for them. They call these Bob Woodward and Carl Bernstein guys from the Washington Post they've heard Dick rail on as "muckraking bastards" and start spilling their guts. (They decide to call themselves "Deep Throat" after Dunst's stoner brother is caught sneaking in to a certain dirty movie with that title.)

Co-written by screenplay rookie Sheryl Longin and director Andrew Fleming ("The Craft"), the script is both sly and silly, re-writing history with tongue firmly in cheek. One of the movie's funniest scenes finds Nixon and Leonid Brezhnev signing an arms treaty under the influence of homemade cookies the girls inadvertently laced with marijuana.

Fleming's direction could have been tighter -- at only 90 minutes, the movie seems long somehow -- and the laughs peter off in the last reel because of all the plot to resolve. But the director's sense of comic timing is impeccable and he doesn't surrender any laughs to the kind of expository dialogue that in many comedies serves only to advance the plot.

He also scored big when his two leads said yes to "Dick." Many of the movie's best chuckles could have fallen a little flat in the hands of flavor-of-the-month teenage stars. But Michelle Williams (who is a much better actress than she gets credit for on "Dawson's Creek") seems to be a natural comedienne as the slightly geeky Arlene, and the supremely talented Kirsten Dunst -- whose subtle sense of comedy was the saving grace of the failed beauty pageant comedy "Drop Dead Gorgeous" -- is perfectly clueless as Betsy, the "brains" of this duo.

There is some unfortunate overacting from several "Saturday Night Live" alumni in the cast. The fact that Woodward and Bernstein are played as bickering rivals instead of pals would have been hilarious if they weren't portrayed by Will Ferrell and Bruce McCulloch (although he's from "Kids In the Hall").

But the non-"SNL" actors are almost uniformly a laugh riot in parts that allow them to play against type, especially mild-mannered Dave Foley ("Newsradio") as a vein-popping Bob Haldeman tough and a mustachioed Harry Shearer ("The Truman Show," "Godzilla") as G. Gordon Liddy.

Although it may seem targeted to teenagers born long after Watergate, who will laugh long and loud at Arlene's and Betsy's not-so-bright antics, the historical comedy in "Dick" will get just as many guffaws from those who remember the 1972-74 scandal and can recognize all the diddled details. Either way, "Dick" is deftly funny.