Quick, what's the first thing that pops into your head when someone says "Newt Gingrich?" Some version of this smug man saying or doing something offensive, that's what. And it's comical that Newt claims he's going to run a "positive" campaign in an effort to earn the Republican presidential nominee in 2012. Positive by what standards? The guy is a ticking time bomb, because he just can't help himself--he's a douche. And you can't take the douche out of the Newt, no matter how hard you try.
So just watch. Newt will either have his bid go up in flames in epic fashion, or he will lose badly in a general election to President Obama. Still, just think about what those debates might be like--the even keeled, well-spoken, and good intentioned Obama against the volatile, scummy, bad-intentioned Newt. And yes, I said scummy. And yes, I meant it. And yes, he IS scummy--just ask his sister or his first two wives or Mitt Romney or Nancy Pelosi.
Frankly I don't see it happening. I think Mitt will still get the nod somehow, and if it's not Mitt, it will be Chris Christie, no matter how many times he can hold press conferences to state the contrary.