Blowhard. Newt Gingrich is a bloviating, pedantic, annoying asshole that just won't seem to leave the national political stage. The guy has been around in politics for the last 30 years, flirting with presidential runs several times - and actually succumbing in a couple of instances - and basically just disrupting the political process wherever he can.
So how is it that this jackass is now leading the Republican primary field? Simple. The guy talks straight, I'll give him that, and these conservative voters like that, regardless of what he's actually saying. Herman Cain had overwhelming positive numbers, and his star was on the rise, until Republican primary voters actually started paying attention to the substance of his 9-9-9 plan, and the implications of his policies (there were a few, I think, but few and far between) - not to mention the sexual harassment and infidelity issues.
The problem with Newt Gingrich, is that he has so much personal and political baggage that he'll have a tough time winning against the equally vacillating Mitt Romney. Also, if Newt is to stay strong, he'll have to get the religious conservatives to look past his spotty (to say the least) past of moral indiscretions (which they're alway wont to do with Democrats, but always seem to be able to do with Republicans). Maybe Newt can salvage his relationship with these right-wing Christians by telling them that he has repented for his past sins, and that he'll need their help and guidance to stay on the straight and narrow moving forward.
All of that being said, I don't see Newt having any staying power. His baggage and his haughty attitude are too much for any electorate to overcome, even one as desperate for alternatives as Republican primary voters are for an alternative to Mitt Romney. Look for all of his old moral shortcomings to come up again, as well as his sometimes more moderate political positions. He's the "flavor of the week", as so many pundits have been using for the literal plethora of Republican primary frontrunners - some running and some deciding against running; Michelle Bachmann, Rick Perry, Sarah Palin, Chris Christie, Ron Paul (unfortunately John Huntsman, the only rational Republican in the race, cannot seem to get any traction) - and his parabolic rise will eventually slide back down the other side.