4. Dave Kovic (as Bill Mitchell) - Dave
The big, long punch-line of Rob Reiner's classic comedy is that nobody as likeable and well-meaning as Kevin Kline's Dave Kovic would ever make it into office, because he's only there after the actual President, Bill Mitchell (Kline) goes into a coma after a raunchy extra-marital outing gone awry. Kovic, who makes some side-cash as a Mitchell impersonator, is drafted in to play the real thing while the various Presidential advisers figure out what to do, but he ends up pretty much playing him for real once the President's prognosis gets increasingly grimmer. This results in some absolutely hilarious escapades involving Mitchell's wife, the First Lady (Sigourney Weaver), but on a more affecting level, Kovic slowly begins to transform from a shade into a political vessel, and ends up enacting some of his own change. With the uncommon humility that pretty much no President has ever had, Kovic was a real every-man, wholly relatable and exactly the sort of guy you'd want on your side. A great Presidential candidate, then.