"Unspeakable Truths" and Public Opinion

Jacob Weisberg at Slate has a wonderful article on the "Four Unspeakable Truths" about Iraq that politicians can't bring themselves to admit.

Here's a sampling:

"When it comes to Iraq, there are two kinds of presidential candidates. The disciplined ones, like Hillary Clinton, carefully avoid acknowledging reality. The more candid, like John McCain and Barack Obama, sometimes blurt out the truth, but quickly apologize."

Why can't they admit the reality of the war? Weisberg attributes it partly to the egotism of politicians: For most of them, telling the truth would mean admitting they made mistakes on Iraq. But a bigger part is fear of public opinion. The polls show that Americans are tired of the war, but that doesn't mean they're ready to admit what a disaster it's been. Politicians on both sides are calculating that if Americans are told the truth, they will punish the messenger.

Are the politicians wrong?