When the Democratic presidential hopefuls line up for a two-hour showdown debate in Manchester on Thursday, it will be a whittled down bunch with no clear front-runner.

With Howard Dean's (search) lead shrinking and just four days remaining until Tuesday's primary, jabs could fly in any direction among the seven remaining contenders, observers said.

As in prior debates, the former Vermont governor will be watched closely, but this time for a different reason.

At a televised debate in Durham last month, Dean was enjoying a commanding lead in the polls and could watch while moderator Ted Koppel (search) put his rivals on the spot, asking why they couldn't close the gap.

Since then, that gap has closed. John Kerry (search) and John Edwards (search) each finished ahead of Dean in Iowa and polls show Wesley Clark (search) and Kerry gaining on Dean in New Hampshire. Clark and Joe Lieberman (search) have been campaigning in New Hampshire while the others focused on Iowa.

"This time the debate will still focus on Dean, but the question will be, 'Gov. Dean, what's going on? Why are you falling back?"' said Andy Smith, director of the University of New Hampshire Survey Center (search).

Dean will have to balance a more aggressive approach in the debate with avoiding the appearance of anger and aggression that some blame for his falloff in Iowa, Smith said.

"He has to be careful not to show the face of Howard Dean that he showed (Monday night)," in a fiery speech following the Iowa caucus, Smith said.

"It's getting to the point where voters are really taking it seriously, they are saying, 'we're electing the leader of the free world,' and they want to see that presidential stature," he said.

Kerry, despite his win in Iowa, is approaching the debate as an underdog, said his New Hampshire spokesman Mark Kornblau.

"He's still behind in New Hampshire, but he's still got a lot of fight in him," Kornblau said.

Dean's New Hampshire campaign spokeswoman Dorie Clark couldn't say if Dean will take a different approach to this debate.

"A lot depends on what the other candidates are saying and doing," Clark said. "Gov. Dean in past months has been under attack by many candidates. But we're focused on trying to put forward a strong positive message about Gov. Dean's vision."

The debate will be the first without Carol Moseley Braun (search) and Dick Gephardt (search).

"It could be a different dynamic," state party chairwoman Kathy Sullivan said. "It could be important if someone has a really good moment or if someone has a really bad moment," she said.

"It's a wide open race right now."

The debate at Saint Anselm College begins at 8 p.m. and will be broadcast live on WMUR-TV and Fox News.

Fox News' Brit Hume and ABC News' Peter Jennings will moderate. Other panelists include WMUR-TV news anchor Tom Griffith and John DiStaso, senior political reporter for The Union Leader.

Moderators were meeting Wednesday and planned to meet again Thursday to plan questions for the debate, said Marty Ryan, Fox News' executive producer for political coverage.

The debate will use a simple format, with questions from each of the panelists. The candidates will be allowed one-minute responses with time for rebuttals. They will be allowed to question each other at the moderator's discretion, Ryan said.

Unlike previous debates, the candidates will not be allowed to give closing statements.

"At this point, we figure everyone has been there, done that," Ryan said