I had the pleasure to hear Newt Gingrich speak followed by a Q&A at Johns Hopkins in Maryland two years ago. The man was very impressive. He batted down naysayers and bombthrowers with ease - turned their own arguments on them and made them look supremely foolish. I can tell you he is more than an idea man - they guy has got superb chops and thinks on his feet pronto.
I'm not questioning his intellect, which is sizeable. I'm questioning his mean streak and ability to bare-knuckle fight, which I think is lacking.