If Hillary Clinton really is pulling out all the stops to topple Barack Obama, it will have to show at Tuesday night's debate in Ohio, her last chance to go toe-to-toe on stage with her Democratic presidential opponent before the Ohio and Texas primaries.

The face-off at Cleveland State University comes one week before the delegate-rich states hold primaries that some in Clinton's inner sanctum have described as make-or-break. Obama has won 11 straight primaries and caucuses, and holds about a 100-delegate lead over Clinton.

Polls show the New York senator losing ground in her firewall contests, and The New York Times reported Tuesday that the Clinton camp is throwing what one aide called the "kitchen sink" of attacks at Obama.

Clinton challenged Obama sharply on health care and foreign policy during their 19th debate together last week in Austin, Texas, and the two have stepped up their rhetoric on those issues since. Primary day is Tuesday, March 4.

Clinton's campaign has also accused the media of going easy on Obama. In return, he says he can feel the step up in Clinton campaign tactics against him.

"I think things have gotten a little hotter in the last couple of days," Obama said at a news conference Tuesday where he collected an endorsement from former campaign rival, Sen. Chris Dodd of Connecticut.

"But these things have gone in sort of ebbs and flows," Obama added. "We're both trying out for quarterback but we're on the same team."

He said he expects a "vigorous debate" Tuesday night.

Clinton criticized Obama on Monday as being ill-prepared to handle foreign policy, ridiculing him for saying he would meet with any head of state without preconditions, an issue that surfaced in the last debate.

Clinton also lit into Obama over the weekend for allegedly using dishonest campaign tactics in mailers criticizing her stances on health care and NAFTA.

She invoked the mailers Tuesday in Lorain, Ohio, saying, "I got a little hot over the weekend down in Cincinnati. You know, because I don't mind having a debate. I don't mind airing our differences, but I really mind it when Senator Obama's campaign sends you literature in the mail that is false, misleading and has been discredited."

One of the fliers accused her of forcing families who can't afford it to buy health insurance, even though Clinton said she'd help low-income families with subsidies.

Spicing the race further was a photograph of Obama that surfaced on the Internet showing him wearing a white turban and a wraparound white robe presented to him by tribal elders in northeastern Kenya.

The Drudge Report Web site posted the photograph Monday and said it was being circulated by "Clinton staffers."

It offered no evidence of that, and Clinton aides said the campaign had not known the photo was being circulated and never sanctioned its distribution.

But Obama's campaign blasted Clinton for engaging in "the most shameful, offensive fear-mongering we've seen from either party in this election."

Obama personally weighed in on the matter Tuesday saying, "I don't think that that photograph was circulated to enhance my candidacy ... Do I think that it is reflective of Senator Clinton's approach to the campaign? Probably not."

Clinton still leads in Ohio polls, though the gap is closing, but aides predict she will win the state. The trend lines in Texas, however, have turned in Obama's favor, according to some polls, which could make Ohio even more critical for Clinton.

Clinton strategists have said that the March 4 primaries will be decisive, one way or the other.

"I think if we lose in Texas and Ohio, Mrs. Clinton will have to make her decisions as to whether she goes forward or not," strategist Harold Ickes said, adding the slight caveat "as she has at the end of every other state," according to the Christian Science Monitor report on his meeting with reporters Monday.

"If she wins those, we then go on to April 22 in Pennsylvania," Clinton campaign national chairman Terry McAuliffe told a business group in Madison, Wis. "If we don't, then she has to make a decision on what she's going to do."

Ohio has become increasingly competitive. A Rasmussen poll taken Monday of 862 likely voters showed Clinton with a 5-point lead over Obama, 48-to-43 percent. That's down from a 14-point lead over the Illinois senator in a similar Rasmussen poll taken Feb. 13.

"Barack Obama is gaining ground," pollster Scott Rasmussen told FOX News. "What we're seeing is a gradual erosion of (Clinton's) core constituencies."

He said trends show she's losing the support of women voters, but retaining support of seniors and lower-income workers.

Bill Clinton, who has been campaigning in Texas while his wife hits Ohio, said Tuesday in Dallas that either his wife or Obama will make history this November -- but his wife will follow through and deliver the change promised by both candidates.

"We're going to have change in the election," he told about 200 people gathered around the pickup truck from which he has campaigned for his wife across Texas. "It's exciting. We're going to break some glass ceiling or another, no matter what happens. But change you can count on is coming from her."

Obama's only pre-debate public appearance was his news conference with Dodd, who said it was time for Democrats to unite for the fall campaign. He denied it was a nudge to Clinton to quit the race.

In addition to Texas and Ohio, Rhode Island and Vermont hold primaries on March 4, with a total of 370 delegates at stake from the four states.

FOX News' Major Garrett, Aaron Bruns and Bonney Kapp and The Associated Press contributed to this report.