I would like to see the Wahabbists kept (and thrown) out of the US as seditious, but that doesn't invalidate what I said.
Open borders is idiocy, CAFTA would find a defender in Adam Smith, while divide-and-conqueror is how successful empires throughout history have dealt with large but disorganized threats. Islam is such a threat. I'm sorry to say post-9/11 through no choice of our own, we have to think and behave like an empire or we will soon cease to be a constitutional republic.
Sometimes they'd have trouble and have to disperse the population of course.
I think that's what you are talking about with "divide and conquer" ~ this dispersal business ~ but with Rome it was rare.