SIOUX CITY, Iowa — Democratic presidential frontrunner Hillary Clinton’s campaign admitted Friday that it planted a global warming question in Newton, Iowa, Tuesday during a town hall meeting to discuss clean energy. Clinton campaign spokesman Mo Elliethee admitted that the campaign had planted the question and said it would not happen again. "On this occasion a member of our staff did discuss a possible question about Senator Clinton's energy plan at a forum,” Elliethee said. “However, Senator Clinton did not know which questioners she was calling on during the event. This is not standard policy and will not be repeated...