Former House Speaker Newt Gingrich continues to surge in the polls. Last week a CBS poll had Herman Cain at 18%, with Mitt Romney and Mr. Gingrich tied at 15%. Even more impressive was the latest McClatchy-Marist poll, which had Mr. Romney at 23%, Mr. Gingrich at 19% and Mr. Cain at 17%. A little over a month ago, Mr. Gingrich was barely above 5% in any poll. Is the former Georgia congressman simply the latest flavor of the month in the wake of the Herman Cain sexual-harassment allegations, or can he actually win? In an interview with me this...