By Ken Feltman (originally published in Politico)
As the front-runner, Mitt Romney has the most to lose. If he performs poorly, the doubts about him will begin to weigh him down. If he comes through with a satisfactory but not spectacular showing, he will not change the battle lines.
With a strong performance, Tim Pawlenty could change the race and become the primary challenger to Romney. But Pawlenty will suffer if he cannot show a more aggressive side. People will start to drift away.
Newt Gingrich must try to make the debate about “big ideas” — the broad themes in which he is at home — and not about politics and legislative detail. This will be a difficult task because other candidates, especially Herman Cain and Michele Bachmann, can compete with Gingrich for ideas, although both Cain and Bachmann must prove that they can put some meat on the bones of their ideas.
With a superior performance, either Cain or Bachmann could shake up the race. If she does well tonight, Bachmann could catch a wave.
The wild card is Rick Santorum. If he goes head-to-head against Romney, for example, he could provide Pawlenty with the opening he needs. If he attacks Pawlenty, Santorum will make Romney’s night easier.
The great unknown is the questions. The order in which topics are raised will play to the strengths of certain candidates, giving them an early advantage and forcing the others to play catch-up.