For the last 50 years, political science has been the easiest major at every college in America, Shepsle says. Rational choice is changing that.

"My Core course [Social Analysis 46, "Thinking About Politics: A Rational Choice Approach"]is probably more rigorous than some course in the Government department that doesn't require the technical mastery that my course requires," Shepsle says.

Yet in spite of the factions' struggle for control over the department, relations between government faculty remain cordial, insiders say, and the conflict has not become personal.

With a new chair of the department in place, who is described as sensitive and fair, the department looks to be able to avoid fracturing from the debates over how best to understand human politics.

Both sides, Hoffmann says, realize that they will need to coexist peacefully.

Still, the renowned professor adds, if he were coming up for tenure today in Harvard's government department, the rational choice contingent would make sure that he wouldn't get it.