Donald Trump's incendiary – and likely unconstitutional – suggestion that the U.S. prevent Muslims from entering the country has set off a firestorm with criticism from both Democrats and Republicans.That hasn't slowed Trump, who is leading the GOP presidential pack."We have no idea who's coming into our country," Trump said during a Monday night campaign rally in South Carolina. "We have no idea if they love us or they hate us. We have no idea they want to bomb us. I have friends who are Muslims, they're great people. They know we have a problem.''In announcing his proposal, Trump cites a...