This was absolutely the best movie I've seen in a very long time. Don't get too caught up in worrying who's Bill, Hillary, etc., just watch some fine performances and some extremely intelligent writing.
The basic point of Primary Colors is that there are a huge number of shades of gray in life, especially in politics. It could also be subtitled The Ten Stupid Things Smart Politicians Do to Screw Up Their Lives.
Primary Colors observes the rough campaign of a southern governor who wants to be president named Jack Stanton (John Travolta) through the eyes of Henry Burton (Adrian Lester), a political operative the Stanton folks are trying desperately to recruit. Even though he's not yet employed by the Stanton team, Henry is dragged from New York to New Hampshire to a 4am meeting with Susan Stanton (magnificently played by the wonderful Emma Thompson). Henry isn't employed as much as he's sucked in by the team, and is soon setting up a campaign headquarters and traveling cross country during the primaries.
Ms. Stanton is portrayed as a stronger political type than her more charismatic, glad-handing husband. She's much more focused on the goal of the White House than he is. Gov. Stanton is much more distractable than she is.
If you've ever wondered why a presidential candidate needs such a big staff, this movie give you insights as to why this is. The spindoctor is wonderfully played by Billy Bob THornton, and the dirt digger/dust-buster is great performance by a particularly off-the-wall Kathy Bates.
One of the interesting points in this movie is just how passive the men are and how active the women are in getting things done. So often in movies, women are window-dressing. Not so in Primary Colors - three cheers to screenwriter Elaine May and directory Mike Nichols.