Newt Gingrich is into auftragstaktik, Tim Murphy of Mother Jones points out.  

That doesn't mean that we should think mission-based orders (and the command philosophy from which that approach is derived) are bad. But it does make me a mite uneasy. Gingrich, someone who had worked alongside him on a defense study panel once told me, is as close as you will find to a modern version of Aaron Burr, by which he meant smart, manipulative, and unethical.

I've only interviewed Newt Gingrich a few times, so I can't say I know him well. That said, this comment, by David Brooks, strikes me as the best analysis I've ever seen of Gingrich:

the two main Republican contenders, we have one man, Romney, who seems to have walked straight out of the 1950s, and another, Gingrich, who seems to have walked straight out of the 1960s. He has every negative character trait that conservatives associate with '60s excess: narcissism, self-righteousness, self-indulgence and intemperance. He just has those traits in Republican form.

As nearly everyone who has ever worked with him knows, he would severely damage conservatism and the Republican Party if nominated. He would severely damage the Hamilton-Theodore Roosevelt strain in American life.

Not persuaded? Here's more. And more. I think President Obama would love to run against Mr. Gingrich.

(HT to Josh K.)