ORONO, Maine — Hillary Rodham Clinton warned Saturday that Democrats will have a hard time running against the "legendary background" of Republican John McCain, and that she is better positioned than Barack Obama to beat the likely GOP nominee.

Campaigning in Maine, which holds nominating caucuses Sunday, Clinton called the Arizona senator a friend but said a McCain presidency would be tantamount to a third Bush administration.

He'd also be a formidable political adversary, she said.

"If our nominee is running against someone with the legendary background of John McCain — Democrats need to think about this," Clinton said. "Because we're picking a nominee we expect to win. We cannot take four more years of more of the same."

McCain, 71, is a decorated former Navy pilot who spent years as prisoner of war in North Vietnam. Known as a political maverick who challenged President Bush for the GOP nomination in 2000, he has since sided with Bush on many key issues, including the war in Iraq.

McCain all but sealed his party's nomination when his top rival, Mitt Romney, exited the Republican field Thursday. Since then, Clinton has begun speaking about the prospect of facing him in the general election.

"When I think about running against Senator McCain, if I'm so fortunate to be the Democratic nominee — you'll never have to worry about being knocked out of the ring," Clinton said to cheers. "I think I can go toe to toe with John McCain every single day."

The former first lady said McCain would make an open ended commitment to keeping troops in Iraq and knew little about the economic problems facing middle class families. She also portrayed him as a strong debater.

At the rally, Clinton never mentioned her Democratic rival by name. But asked later by reporters about recent polls suggesting Obama would fare better than she would against McCain in a general election, the New York senator offered a detailed rebuttal.

"I'm actually drawing from voters a Democrat needs to draw from to establish a strong lead against Senator McCain — voters making less than $50,000, Latino voters, women, which has always been part of the Democratic nominee's base," she said. "I have every confidence we can win back the voters Senator Obama has been attracting."

Obama has shown considerable strength among young people, affluent and educated voters, and blacks.

Clinton also said voters would be better able to envision her as a potential commander in chief running against McCain and that she presented a starker contrast on issues.

"I don't think it's helpful for the Democratic nominee to have given up on universal health care," Clinton said. She has repeatedly criticized Obama for offering a health care plan that would not require everyone to purchase insurance.

On a separate matter, Clinton said she had sent a letter to NBC News president Steve Capus criticizing what she called a "troubling pattern of demeaning treatment" of her campaign by the network's cable arm.

On Friday, MSNBC anchor David Shuster was suspended for suggesting that Chelsea Clinton had been "pimped out" by the Clinton campaign by asking her to phone superdelegates on her mother's behalf.

Shuster has since apologized, but Clinton said Saturday she wasn't sure she would agree to participate in a debate with Obama on the network scheduled for Feb. 26.

"I am a mom first and a candidate second and I found the remarks incredibly offensive," she said.

In the letter, which the campaign released, Clinton urged Capus and others at NBC to "do your jobs as journalists and commentators and still keep the discourse civil and appropriate."