Newt Gingrich once called himself "the most seriously professorial politician since Woodrow Wilson."

But that was 1995, and the "Contract with America" co-author had just helped to propel Republicans into power in the House for the first time in 40 years, and Gingrich himself into the speaker's role. Even the rarely modest Gingrich had reason to gloat.

Just two years later, of course, he had become the first speaker ever punished by the House for ethics violations, and the end was in sight for both his leadership and congressional career.

Gingrich's troubles stemmed in part from his professorial work, a 1994 college course he had taught in Georgia....