"Today my opponent continued his pattern of twisting in the wind," Bush said at a rally in New Hampshire. "He apparently woke up this morning and has now decided, no, we should not have invaded Iraq, after just last month saying he would have voted for force even knowing everything we know today."
John Kerry (search), a four-term Massachusetts senator, voted to give Bush authority to wage the war; the presidential hopeful said in August he would have voted that way even had he known there were no banned weapons in Iraq.
"Incredibly, he now believes our national security would be stronger with Saddam Hussein (search) in power and not in prison," Bush said. "He's saying he prefers the stability of a dictatorship to the hope and security of democracy.
"I couldn't disagree more, and not so long ago, so did my opponent," Bush added, quoting Kerry as saying recently, "Those who believe we are not safer with his capture don't have the judgment to be president or the credibility to be elected president."
Bush campaign officials had promised an attack that would accuse the Democratic senator of advocating a "retreat and defeat" policy in Iraq.
Earlier in the day, Kerry told supporters during a campaign stop that no responsible commander in chief would have invaded Iraq knowing Saddam didn't possess weapons of mass destruction and wasn't an imminent threat to the United States.
"Yet today, President Bush tells us that he would do everything all over again, the same way. How can he possibly be serious?" the candidate said during a speech New York University, where he slammed Bush on all things Iraq.
He said Monday that Bush's actions could lead to an unending war.
Kerry makes a distinction between his vote, as a senator, to grant Bush war-making authority and Bush, as commander in chief, actually taking that fateful step. Republicans have accused Kerry of flip-flopping on the war and other issues.
Kerry's speech came one day before of Bush's scheduled address to the U.N. General Assembly. Bush planned to strike back at Kerry's increasingly aggressive criticism on Iraq, aides said.
Bush attends a fund raiser for the Republican National Committee in New York City on Monday night.
Bush campaign spokesman Steve Schmidt said Kerry's goal of pulling U.S. troops out of Iraq in his first term sends "a clear signal of defeat and retreat to America's enemies that will make the world a far more dangerous place."
Bush had a warm reception in New Hampshire, the only state in New England that he carried in 2000 and where he holds a lead over Kerry.
Just six weeks before the presidential election, a new poll of New Hampshire voters puts Bush ahead of Kerry in that state. The Mason-Dixon poll for MSNBC and Knight-Ridder had Bush at 49 percent and Kerry at 40 percent. The poll of 625 likely voters was conducted Monday through Wednesday. It had a margin of error of plus or minus 4 percentage points.
A poll in August and two in late July showed Bush and Kerry about even or Kerry slightly ahead in New Hampshire.
Kerry: 'We Have Traded a Dictator for a Chaos'
Kerry said Monday of Bush, "Is he really saying to Americans that if we had known there were no imminent threat, no weapons of mass destruction, no ties to Al Qaeda, the United States should have invaded Iraq? My answer is resoundingly no because a commander in chief's first responsibility is to make a wise and responsible decision to keep America safe."
"Saddam Hussein was a brutal dictator who deserves his own special place in hell," Kerry said. "But that was not, in itself, a reason to go to war. The satisfaction we take in his downfall does not hide this fact: We have traded a dictator for a chaos that has left America less secure."
U.S. Senate Foreign Relations Committee Chairman Richard Lugar, R-Ind., said after the Massachusetts senator missed almost 24 open oversight hearings on Iraq, in which lawmakers were given chances to offer "timely criticism" and to help Bush shape U.S. policy.
"Without offering any alternative plans that our Committee and the American people could debate, Senator Kerry has tried to argue that President Bush is concealing the truth and the potential that events in Iraq will become worse," Lugar's statement said. "In fact, with the participation of the administration, we have been publicly airing and examining all scenarios, including the worst outcomes."
Kerry offered his own four-point plan starting with pressing other nations for help.
— Get more help from other nations.
— Provide better training for Iraqi security forces.
— Provide benefits to the Iraqi people.
— Ensure that democratic elections can be held next year as promised.
"If the president would move in this direction ... we could begin to withdraw U.S. forces starting next summer and realistically aim to bring all our troops home within the next four years," Kerry said. "This policy has been plagued by a lack of planning, an absence of candor, arrogance and outright incompetence."
Kerry said Bush's two main rationales — weapons of mass destruction and a connection between Al Qaeda and the Sept. 11 attacks — have been proven false so far by weapons inspectors and the bipartisan commission investigating the attacks.
Bush "hitched his wagon to the ideologues who surround him, filtering out those who disagreed, including leaders of his own party and the uniformed military," Kerry said. "The result is a long litany of misjudgments with terrible consequences."
Republicans Speak Up
Some Republicans are also voicing concern about the president's leadership in Iraq. Lugar said problems with reconstruction show there is "incompetence in the administration" and noted that Congress appropriated $18.4 billion a year ago this week for reconstruction. No more than $1 billion has been spent.
"This is the incompetence in the administration," Lugar said on ABC's "This Week."
Lugar added that the United States needs to train more Iraqi police officers and better coordinate military bombings with Iraqi forces "so that we do not alienate further the Iraqi people by intrusions that are very difficult and are costly in terms of lives."
Sen. John McCain, R-Ariz., told "FOX News Sunday" that he would like to see the president be more clear about the dangers in Iraq.
The former POW said Bush was not being "as straight as we would want him to be" about the situation.
Some lawmakers even invoked Vietnam.
"The fact is, a crisp, sharp analysis of our policies is required. We didn't do that in Vietnam, and we saw 11 years of casualties mount to the point where we finally lost," Sen. Chuck Hagel, a Vietnam War veteran who is co-chairman of Bush's re-election committee in Nebraska, said on CBS' "Face the Nation."
FOX News' Wendell Goler and The Associated Press contributed to this report.