In politics, what goes around comes around — especially if you’re running for president. In 1988, then-Congressman Newt Gingrich’s success in bringing down Democratic House Speaker Jim Wright on ethics charges helped propel the Georgian into the House GOP leadership. But in 1994, then-Speaker Gingrich became the subject of his own lengthy ethics investigation. Although he was not found guilty on any of the 84 charges, the probe resulted in a reprimand from the House Ethics Committee, a $300,000 fine, dwindling support from the Republican caucus and his eventual resignation from Congress. “I’m willing to lead,” Gingrich said, announcing his...