the undercard debate with carly fiorina, rick santorum and mike huckabee. the candidates that main the cut or donald trump, ted cruz, chris christie, jeb bush and john kasich. the republican front-runner, donald trump will be at the center podium. he's hanging on to a big lead in new hampshire. 18 points according to a new poll. in iowa, he's locked in that tight battle with ted cruz. a new quinnipiac poll gives him a two-point advantage. last night on "the tonight show," trump told jimmy fallon he's been preparing for this debate for the last 30 years. >> debates have been interesting. we have one on thursday night coming up, a big one. >> that's right. >> i hope to do well. twho knows? you never know folks, you never know. the debate will be on the fox business network on thursday night. the undercard at 6:00 p.m. how much will trump and cruz go after it after the mounting