Dave Kovic is a nice guy who runs an employment agency in Washington DC.  He is a man who cannot rest when one of his clients needs a job, but is otherwise undistinguished . . . except that he happens to look exactly like the president of the United States, Bill Mitchell.  When the president wants to sneak away for a quickie with his mistress, Dave is thrilled to be recruited by the Secret Service to act as a stand-in.  But then the president unexpectedly has a fatal stroke, and the White House chief of staff, evil genius Bob Alexander, decides to use Dave as a permanent front man in order to avoid turning over the reins of power to the kind and decent vice president, Charles Nance.

Dave dimly understands that this is wrong, but allows himself to be persuaded, and settles into the role of president with great gusto and enjoyment.  The only sticking point may be trying to fool the first lady, Ellen Mitchell.  Although the first marriage is over in all but name--Bill and Ellen hardly even talk in private because she's so angry about his philandering, deviousness, and mean-spirited political beliefs--they still appear together in public.  Just how long it will take the first lady--and the country as a whole--to catch on?

This movie is proof that it isn't what you do, it's how you do it: Ivan Reitman's direction and Gary Ross' screenplay use intelligence and warmhearted sentiment to make Dave into wonderful lighthearted entertainment.  Dave takes that old plot about an ordinary person who is suddenly thrust into a position of power, and finds a fresh way to tell it.

The plot unfolds with elements that would be at home in a Frank Capra movie, which Reitman crosses here with some sly political satire.  One of the movie's charms is the way it toys with our expectations.  Ellen Mitchell is a smart and proud woman with a good heart; she detests her husband's two-timing politics and personal infidelity, and spends so little time with him that perhaps the deception will work.  There's even poetic justice in the way the movie resolves everything; both private and public agendas are fulfilled.

Much depends on the supporting performances, and Langella is superb as the oily manipulator who thinks he can run the country as a puppet-master.  Kevin Dunn does an excellent job as Langella's right-hand man, Kingsley portrays the vice president with dignity and forbearance, and the always dependable Charles Grodin plays a small but essential role as Dave's best friend.  But the heart of the film is really the relationship between Dave and the first lady, who wander about their cavernous and lonely quarters in the White House like a couple of moonstruck teenagers.

The subtext of Dave is simple:  If people in power only behaved sensibly and with good will, a lot of our problems would solve themselves.