Ohio Sen. Rob Portman says he will not run for president in 2016, choosing instead to seek a second term in the Senate. Portman, a former White House budget chief and U.S. trade representative, said he can play an important role as a member of the new Republican majority in the Senate, where he wants to help break the gridlock that has largely paralyzed Congress for the past two years. A former congressman who was on Mitt Romney’s short list of potential running mates in 2012, Portman was one of four senators considering a presidential run. The others, Rand Paul of Kentucky, Marco Rubio of Florida, and Ted Cruz of Texas, are still weighing a decision.