Kerry, who was President Bush's 2004 rival for the White House, criticized the administration's handling of the Iraq war, citing two recent developments.

The Massachusetts senator mentioned the classified National Intelligence Estimate, which suggests the Iraq war has helped recruit more terrorists, and a new book, "State of Denial," by journalist Bob Woodward that contends Bush misled the country about the war.

"If they want to have a debate on security, I've always said let's have the debate," Kerry said. "With the new facts we now have available, I think Americans are going to be realizing that this is the Katrina of foreign policy."

Kerry was referring to Hurricane Katrina that struck the Gulf Coast in 2005. The administration was widely criticized for its handling of the aftermath of the devastating storm.

"I think as you go into '08, all these people who have been jumping up and down about this policy and ignoring the truth have misled America, and they have misled us into the most costly, disgraceful and unnecessary use of American might," Kerry said.

Kerry is considered a potential presidential candidate in 2008. He was in Iowa campaigning for Michael Mauro, the Democratic candidate for secretary of state.

"It is disgraceful what this administration has done to mislead America and denigrate legitimate dissent," Kerry said. "To me it one of the most serious, catastrophic moments of irresponsibility in the conduct of American security policy that I've ever seen."

Tracey Schmitt, a spokeswoman for the Republican National Committee, dismissed Kerry's criticism, saying, "While John Kerry continues to fight for any shred of political relevance, our president continues his fight against terrorists committed to taking away our most basic freedoms."