WASHINGTON (AP) - President Bush said Wednesday the responsibility for invading Iraq based in part on faulty weapons intelligence rested solely with him, taking on the issue in his most direct and personal terms in the 1,000-plus days since the war's first shots.

"It is true that much of the intelligence turned out to be wrong," Bush said. "As president, I'm responsible for the decision to go into Iraq."

The president's mea culpa was accompanied by a robust defense of the divisive war.

"Saddam was a threat -- and the American people and the world is better off because he is no longer in power," Bush declared, as he has before.

Democrats were not moved by Bush's speech, the last of four designed to boost his credibility on the war and the public's backing for it.

"There was no reason for America to go to war when we did, the way we did, and for the false reasons we were given," said Sen. Edward Kennedy, D-Mass.

Bush offered few qualms about the failure to find any weapons of mass destruction in Iraq. He said foreign intelligence agencies -- including several for governments who didn't back his decision to invade -- also believed before the war that Saddam Hussein possessed them. And he said his administration has begun making changes to the U.S. intelligence apparatus to head off future errors.

The president also contended the Iraqi president had intended to restart weapons programs.

As in the past, Bush acknowledged no regrets about launching the war despite the problems with his initial justification. He revisited a long list of other previously cited reasons, including Iraqi violations of a no-fly zone in its airspace, Saddam's invasion of Kuwait a decade earlier and Iraq's defiance of United Nations resolutions.

"My decision to remove Saddam Hussein was the right decision," the president said to polite applause from his audience at the Woodrow Wilson International Center for Scholars, a nonpartisan forum for the study of world affairs.

Bush has repeatedly noted that the decision to go to war was his responsibility. And he has acknowledged for more than a year that most of the intelligence behind the claims of Saddam's weapons programs turned out to be faulty. But he has never linked the two so clearly and so personally.

On the eve of parliamentary elections in Iraq, Bush's speech was meant to wrap up an aggressive push-back against war critics with an overarching explanation, nearly three years later, of why he went into Iraq and why he believes U.S. troops must remain there.

Bush predicted a higher turnout than in earlier balloting of Iraq's minority Sunni Arabs in Thursday's voting, which will establish Iraq's first permanent, democratically elected government. The Sunnis provide the backbone of the insurgency and largely shunned Jan. 30 elections for an interim Parliament that wrote the nation's constitution. Their participation was higher in the October election to adopt the constitution.

But the president also said that Americans shouldn't hope for violence to wane, and shouldn't even expect to know results before early January.

"We can ... expect that the elections will be followed by days of uncertainty," he said. "It's going to take awhile."

Wednesday's remarks followed a pattern of more frank talk from Bush on Iraq. Each installment in the recent round of Iraq speeches, which began last month at the Naval Academy, has included descriptions of fixes for early mistakes and sober assessments of remaining challenges.

That reflects the majority of Americans who, confronted with daily doses of bad news and rising death counts in Iraq, disapprove of Bush's policies there and question the outlook for victory. For instance, a new poll by the Pew Research Center for the People & the Press found that most people see progress in areas such as establishing democracy and training Iraqi security forces but are split on whether the United States is defeating the insurgents.

Answering critics who have said he's offered no definition of victory in Iraq, Bush offered a succinct summation.

"Victory will be achieved by meeting certain objectives: when the terrorists and Saddamists can no longer threaten Iraq's democracy, when the Iraqi security forces can protect their own people and when Iraq is not a safe haven for terrorists to plot attacks against our country," he said. "These objectives, not timetables set by politicians in Washington, will drive our force levels in Iraq."

Still, some said they had hoped to hear more specific benchmarks.

"The American public, the Iraqi people and our brave troops still don't have any clarity about the U.S. military mission in Iraq," said Sen. Russ Feingold, D-Wis.

The president's approach received a warmer welcome from several House Democrats whom Bush hosted at the White House for a top-level Iraq briefing before his speech.

"There was a dose of reality that I have not heard before," said Rep. Steve Israel, D-N.Y.