At an event in New York some months ago, I went over to Sen. Edward M. Kennedy and told him precisely how I felt about him: Sorry.

I was sorry that I had not listened to him about George W. Bush and even sorrier that I had not listened to him about the war in Iraq, which he had opposed. If it is not too late, I recommend that John Kerry do what I am now doing: Pay attention to Teddy Kennedy and what he has to say.

On Friday Kennedy delivered a Senate speech that's worth a gaggle of campaign consultants of the sort Kerry has been hiring in lieu of plumbing his own gut. Kennedy accused the Bush administration of "arrogant ideological incompetence."

It's hard to be either more succinct or more on target. The little phrase sums up all that ails both Bush and his administration -- everything from a misguided crusade to liberate Iraq (and the Middle East) from despotism to the strut of the president himself. It fingers the reason why Bush and his boys went to war in Iraq, expecting what Kennedy called "a cakewalk." This was the triumph of ideology over common sense, a belief propounded by neoconservatives within and without the administration that beneath every Iraqi lurked the Music Man, and U.S. troops would be greeted by, at a minimum, 76 trombones. A predisposition to believe your own fantasies makes a very sweet sound indeed.

In his speech, Kennedy several times mentioned Bush's "mission accomplished" mentality, which "left our armed forces in Iraq underprepared, understaffed and underled for the mission that was only just beginning." Kennedy quotes Don Rumsfeld, who, with his characteristic bluntness, refused to say precisely how long the war might last. But it would not, he assured us, be more than "six months." As for Vice President Cheney, Kennedy has him on the record, too. American troops would "be greeted as liberators," Cheney said. This is the man Bush took on his ticket for his wisdom.

The virtue of Kennedy's speech is that it makes clear that all the missteps leading up to the war and all the blunders afterward were not mere mistakes but the product of an ideology that had seized the administration and rendered it inept. The Bushies operated on an expectation of how things should be and not, as governments should, on empirical knowledge seasoned by strong cynicism. They so much believed that things would be as they wanted them to be that they embarked on a latter-day Children's Crusade. Where, oh where, were the adults?

Liberals, too, can be blind practitioners of "arrogant ideological incompetence." The dreamy belief in the hidden virtues of all the poor or in the idea that money makes the difference between good and bad schools are examples of ideology smothering common sense. I suppose, too, you can throw in the Vietnam War, which started with arrogance, proceeded to incompetence, and managed to straddle both liberal and conservative ideologies. The Bush administration, though, proceeded in spite of the lessons of Vietnam, so certain was it of its course. For it -- and, yes, for those of us who supported it -- that was indeed arrogance.

Once I wrote a column disparaging Sen. Chuck Robb. Later he stood in the Senate and delivered a gutsy speech against gay-bashing and I gladly had to eat my words. Years later, I ridiculed Sen. Bob Graham for the diaries he kept. Now he has written a worthy book damning the Bush administration for its many intelligence blunders, and again I bow in regret. Finally, I long ago stopped paying hard attention to Ted Kennedy, but now I find him a typhoon of common sense and intelligent indignation. He has not lost the gift of outrage.

Kennedy did not vote to authorize George W. Bush's war. Kerry's problem is that, whatever else he intended, he did. Had he Kennedy's zest for boldness, he would have admitted a mistake and moved on. But he chose a supposedly safe and overly nuanced route that has left him tongue-tied. Kennedy, who was right from the start, is not similarly burdened, but his formulation of "arrogant ideological incompetence" can be used by Kerry anyway. In three words, it answers the question of why we are -- still and in coming years -- in Iraq. All the rest is commentary.