In the debate, Kerry responded (a) "I've never wavered in my life," but (b) "certainty" can get you in trouble. And when moderator Jim Lehrer asked of Kerry: "You've repeatedly accused President Bush, not here tonight but elsewhere, of not telling the truth about Iraq - essentially of lying to the American people about Iraq; give us some examples of not telling the truth," Kerry answered, "Well, I've never, ever, used the harshest word as you just did."

Wrong - at least twice. On Sept. 20, 2003, in Claremont, N.H., Kerry said: "This administration has lied to us. They have misled us. And they have broken their promises to us." And on Dec. 8, 2003, the Boston Globe reported: "Kerry also told a New Hampshire newspaper editorial board Friday that Bush had 'lied' about his reasons for going to war in Iraq, a word Kerry has been reluctant to use publicly for months. Yesterday he said he did not plan to use the word again."

In debates (and to the extent these exercises are, in fact, debates), the winner tends to be the one who stays on message and speaks with sincerity in language understood by (and used by) his audience. Bush is hardly glib. Yet he shares not only the language but the principles and conservative values of the majority of American voters. So it is easy for him to project as sincere.

Kerry is caught between his leftist values and their rejection by a lopsided plurality of the electorate, which describes itself as conservative. The liberal trying to sound the moderate he is not, has to speak on all sides of the issues - and thereby presents as a vacillating purveyor of mixed message. He comes across as too slick by half. Professor Osterweis - the delivery and content man - likely would tell Kerry he cannot sell himself as sincere if he lacks the courage to speak his convictions.

That is perhaps Kerry's foremost campaign-trail problem, as formulated by the late novelist John Marquand in "Sincerely, Willis Wayde," wherein the protagonist tells his wife: "I try to be sincere, really I do. But sometimes it's a problem, how to be sincere." A Kerry failure to prevail on Nov. 2 will owe largely to a failure to meld his style with a sincerity about the substance of his beliefs.