In an interview with The Associated Press, Clinton also said she would not cede black votes to Barack Obama and that she had proven as a U.S. senator that gender is irrelevant.

Of her husband, the former president, she said he would have a role in the campaign but "I'm the one running for president."

Clinton was making her first campaign swing through this early nominating state, which twice voted for Bill Clinton for president. She met with key activists and held a raucous town hall meeting with 1,500 cheering backers and hundreds of journalists.

"I have said clearly and consistently for quite some time that I regret the way the president misused the authority," said Clinton. "He misled Congress and the country on what he was seeking and what he intended to do."

The responsibility Clinton said she accepts was helping clear the way for Bush's path in Iraq.

"I take responsibility for having voted to give him that authority," she said. "My focus is on what we do now. That is the proper debate."

In the interview:

_Clinton said she expected to attract black votes even though Obama, the freshman Illinois senator, has caught fire. "I'm going to be asking for the votes of all Americans," she said.

_Her husband will play a key role in her campaign, though she'll make it clear she's the candidate. "At the end of the day when voters make up their mind, I will have a great team around me, including him," she said.

_Her experience in a failed health care reform effort in the White House does not dampen her effort to again deal with the issue. "I think it makes me a more effective messenger," she said. "I now what the roadblocks and obstacles are."

_Clinton expressed confidence voters are ready to elect a woman president. "It's one of those issues that evolves over time," she said. "I'm very confident I can see it unfold."

In her first campaign swing through Iowa, the New York senator told party activists that Democrats in 2008 will face "someone on the other side who will be very tough and strong, even bellicose perhaps."

That likely was a reference to Arizona Republican Sen. John McCain, who has taken a hard line in supporting more U.S. troops to Iraq, as Bush has announced.

The former first lady also said has learned the lessons of the last two presidential campaigns, both lost by Democrats who responded slowly to criticism.

"When you are attacked, you have to deck your opponent," Clinton said. "I have been through the political wars longer than some of you have been alive. We've got to be prepared to hold our ground and fight back."

Clinton, who announced her candidacy last weekend, said Democrats cannot concede the security issue.

"We have to nominate someone who can have the trust and confidence of the American people to make the tough decisions as commander in chief," she said. "That is the threshold issue."

Her initial foray in Iowa was far different from the traditional caucus campaigning, with a few people in a living room. More than 1,500 people jammed a high school gymnasium for a town hall-style meeting. Some 150 reporters and photographers chronicled the event.

Earlier, she met with state Democrats at the party's headquarters.

Attention focused on Iraq and her vote to authorize the use of force ahead of the U.S.-led invasion in March 2003. Presidential rivals such as former North Carolina Sen. John Edwards now say the vote in support was a mistake.

"There are no do-overs in life," Clinton said. She says Congress received bad information going into the vote and that she would have voted differently given what she knows now.

"As a senator from New York, I lived through 9/11 and I am still dealing with the aftereffects," Clinton said. "I may have a slightly different take on this from some of the other people who will be coming through here."

Clinton said her view is that the nation is engaged in a deadly fight against terrorism, a battle that she contends Bush has botched.

"I do think we are engaged in a war against heartless, ruthless enemies," she said. "If they could come after us again tomorrow they would do so."

Clinton has urged a cap to the number of U.S. troops in Iraq, but has refused to go along with suggestions that Congress use its power of the purse to bring the war to a halt.

"This will be a problem that will be left to the next president," the senator said. "We've got to figure out now, given where we are, how we go forward."

Copyright 2007 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.