Billionaire real estate mogul Donald Trump is buffeted by controversy, but still tops the Republican presidential field a new national poll from the Pew Research Center. The survey’s punch-in-the-gut finding, however, is that ex-Florida Gov. Jeb Bush has fallen to 4 percent. The Bushes have been the gold standard in GOP politics, but Jeb Bush has made news only with gaffes — such as his remark, “Stuff Happens!”, on the Umqua Community College killings in Oregon.