This is part of Hello, Trumpworld, Slate’s reluctant guide to the people who will be calling the shots now—at least for as long as they last in Washington. It is one of the most pervasive, troubling archetypes of the Trump era: the older person who, over the course of the past decade, has migrated from run-of-the-mill conservatism to a worldview dominated by conspiracies and violence. Tom Homan, who will serve as Donald Trump’s “border czar,” may be the most powerful product of this Thin Blue Line to Tinfoil Hat pipeline (or Thin Blue Tinfoil Hat for short). What Americans might...