President Obama, in need of a strong performance, is in attack mode throughout the town-hall-style debate. Mitt Romney holds his ground, often challenging the incumbent in a prosecutorial manner.HEMPSTEAD, N.Y. — In a town-hall-style debate that was supposed to focus on questions from ordinary voters, President Obama and Mitt Romney circled each other on the stage and engaged in finger-pointing displays, arguing over energy, immigration and the deadly attack on the U.S.