RACHEL MADDOW (HOST): From the Ohio speech, the terrorism speech, which I thought was just a fascinating turn, and it was on this issue of extreme vetting. What he's describing as extreme vetting for people who want to immigrate to this country. And what he said was, "in the Cold War, we had an ideological screening test. The time is overdue to develop a new screening test for the threats we face today." What is that about?