In an interview with ABC News’ Jake Tapper in Iowa Thursday, former House Speaker Newt Gingrich confidently proclaimed “I’m going to be the nominee.”

So what’s standing between Newt and the brass ring?

1) Iowa debates: These debates have been the single greatest reason for Newt’s rise, in large part because he’s been able to remain above the fray. It’s hard to believe he’ll be able to remain out of the line of fire at the December 10 ABC debate in Des Moines. How he reacts–both in tone and substance–will be critical to his chances to remain on top.

2) His past: While his rivals snipe about his Washington ties and question his commitment to conservative orthodoxy, none have directly challenged him in paid advertising. Yet. Meanwhile, as our ABC team in Iowa witnessed yesterday, there is an active underground effort to discredit the former House speaker. Found tucked on windshields of every car parked at two events Gingrich attended yesterday were anonymous fliers that attacked his record on issues ranging from his support for Medicare Part D to his lucrative contract with Freddie Mac.

3) Organization: Even Gingrich admits that he’s not where he needs to be in terms of campaign organization in Iowa. One smart GOP insider in the state tells us that while Gingrich has gotten an enthusiastic response from Iowa GOPers this week, he’s yet to prove that he can turn out these voters on his own.

4) Self-Discipline: When Newt is on, he’s good. But, when he gets off-message he often digs himself into bigger problems. Can he keep himself and his message focused as the pressure of being a frontrunner intensifies?

–Amy Walter, Political Director, ABC News