Rich Lowry has Senator McCain's number:

. . . on almost any issue not directly related to the war on terror, McCain can be expected to come down on the side not of the conservatives, the liberals, the Republicans or the Democrats, but of the journalistic clerisy. Determine what the conventional wisdom of the press is (in this case that the Swift Boat vets are discreditable), and there John McCain will be, standing like a stone wall.

Lileks has Senator Kerry's number:

Some men run because they truly wish to shake up the old order. Alan Keyes ran because he believed passionately in his ideals, but unfortunately he struck many people as somewhat insane. Ronald Reagan ran because he believed in a new direction, and inhabited his ambitions with ease and grace.

John Kerry is running because his turn has finally come. See also: Bob Dole, Michael Dukakis, Walter Mondale. And Richard Nixon.