New York ? Democratic presidential candidate Sen. John Kerry Monday unleashed some of his harshest attacks yet on President Bush’s handling of the Iraq war calling it a “colossal failure of judgment.”

“The president has said he miscalculated in Iraq and that it was a catastrophic success,” Kerry told an audience at New York University. “In fact, the president has made a series of catastrophic decisions from the beginning in Iraq. At every fork in the road, he has taken the wrong turn and led us in the wrong direction.”

Kerry said Bush rushed into Iraq without any post-war plan. “Yet today Bush tells us he would do everything all over again the same way. How can he possibly be serious?” Kerry said.

Kerry said national security is a key campaign issue, but that Bush has misled the country on everything from weapons of mass destruction to the deteriorating situation in Iraq.

“The president claims it is the centerpiece of his war on terror,” Kerry said. “In fact, Iraq was a profound diversion from that war and the battle against our greatest enemy, Osama bin Laden and the terrorists. Invading Iraq has created a crisis of historic proportions and, if we do no change course, there is the prospect of a war with no end in sight. …

“Saddam Hussein was a brutal dictator who deserves his own special place in hell. But that was not, in itself, a reason to go to war. We have traded a dictator for a chaos that has left America less secure.”

Kerry’s critique was a sharp departure from the campaign’s strategy to focus the economy and health care, issues on which polls show that the Democrat has a clear advantage.

But the bleak outlook for Iraq disclosed last week in a National Intelligence Estimate, along with questions from key Republican senators about the administration’s competence, brought the issue to a “more dominant position,” said senior Kerry adviser Joe Lockhart.

‘Late Show’ appearance

Kerry later made an appearance on “The Late Show with David Letterman.”

Besides reading a “Top 10” list, Kerry also poked fun at the tedious debate negotiations between the rival campaigns. Kerry said he wanted running mate John Edwards to stand in the vice presidential debate, but Cheney wanted to sit. “We compromised and now George Bush is going to sit on Dick Cheney’s lap,” he said.

Kerry’s “Top 10 Bush Tax Proposals” are:

10. No estate tax for families with at least two U.S. presidents.

9. W-2 Form is now Dubya-2 Form.

8. Under the simplified tax code, your refund check goes directly to Halliburton.

7. The reduced earned income tax credit is so unfair, it just makes me want to tear out my lustrous, finely groomed hair.

6. Attorney General (John) Ashcroft gets to write off the entire U.S. Constitution.

5. Texas Rangers can take a business loss for trading Sammy Sosa.

4. Eliminate all income taxes; just ask Teresa (Heinz Kerry) to cover the whole damn thing.

3. Cheney can claim Bush as a dependent.

2. Hundred-dollar penalty if you pronounce it “nuclear” instead of “nucular.”

1. George W. Bush gets a deduction for mortgaging our entire future.

Kerry has another television appearance this morning, on “Live with Regis and Kelly.”