He’s not letting up. The outspoken presidential candidate doubled down on his criticisms of Sen. John McCain, refusing to apologize for disparaging remarks he made in Iowa about the POW’s “hero” status. Trump defended himself in an op-ed by accusing McCain of abandoning other vets. Appalled, some fellow Republicans asked Trump to throw in the towel — and McCain called for an apology to veterans. But a new poll puts Trump 11 points ahead of his Republican 2016 rivals, meaning that even if he’s dividing his own party’s leaders, the base seems to savor the confrontational tone.