Newt Gingrich has ramped up his attacks on Mitt Romney as a heartless leveraged buyout executive for his years at Bain Capital, asking reporters in Manchester on Monday, “Is capitalism really about the ability of a handful of rich people to manipulate the lives of thousands of other people and walk off with the money? Or is that, somehow, a little bit of a flawed system?” But Mr. Gingrich was himself on an advisory board for a major investment firm that had a similar business model, Forstmann Little, a pioneering private equity firm co-founded in 1978 by Theodore J. Forstmann...