On the line is Sen. Hillary Clinton's continued presidential viability. Losses in Ohio and Texas a week from today could effectively kill her chances of winning the nomination against Sen. Barack Obama, who has reeled off 11 straight wins.

"Clearly for Clinton and Obama, the stakes are much higher here than any other debate," said former U.S. Rep. Dennis Eckart, a Cleveland Democrat. "Obama can close it out on March 4 (or) Clinton can live to fight another day on March 4. All of that comes to a head in this debate."

Polls show Clinton leading Obama in Ohio, but the race has tightened. With everything on the line in the Democratic race, the 90-minute showdown at Cleveland State University, which will be shown at 9 p.m. on NBC and MSNBC, is expected to be widely viewed.

"People are looking at this as a pretty critical moment," said Stephen Koch, professor of communication and a debate specialist at Capital University.

"People are looking at it to see if Clinton can adjust and to see if Obama will continue to build. Clearly, Clinton is looking for a way to deal with the Obama phenomenon, and that places pressure on her."

Bill Carrick, a Los Angeles-based Democratic consultant who worked for former President Clinton's 1992 and 1996 campaigns, said the Cleveland debate "is probably the last opportunity that Sen. Clinton is going to have to make the case both for herself and against Sen. Obama that will be unfiltered."

Carrick said Obama, who has defined himself as a candidate of hope and unity, "would like to avoid a food fight" but almost certainly will press Clinton on the contentious issue of the North American Free Trade Agreement. Obama has criticized Clinton for supporting the trade agreement that he says has cost Ohio jobs. Clinton has accused Obama of distorting her position on NAFTA.

Some political observers such as Brad Coker, managing director of Washington-based Mason-Dixon Polling & Research, said Clinton probably will try "to draw blood" in the debate.

"I'm expecting the punches to start flying in this debate because at this point if she loses Texas and Ohio, she's really done for," Coker said. "She has to put him back on his heels. If she doesn't do it, she's just running up the white flag … The question is, how much does she turn up the heat, and will it be effective or will it just make people angry?"

Obama said Sunday in Lorain that after 19 debates, he doesn't expect much new ground to be covered in the Cleveland matchup.

"Let's face it: I can make all her arguments on behalf of her candidacy at this point, she can make all of my arguments on behalf of my candidacy," he said.

Asked whether he expected a more combative debate, Obama said, "My goal continues to be presenting my case to be president; I'm not in this to tear anyone down. We have some differences on policy."

Issac Baker, Clinton campaign spokesman, declined to discuss what tack she will take in the debate.

"I think she's going to come in prepared to make the strongest case to Ohioans that she is the candidate to start turning this economy around and begin delivering real solutions to their problems," Baker said.

Dispatch reporter Mark Niquette contributed to this story.

jhallett@dispatch.com