Trump has reconquered his party by setting its base on fire. Tens of millions of Americans perceive their world through black clouds of his smoke. His deepest source of strength is the bitter grievance of Republican voters that they lost the White House, and are losing their country, to alien forces with no legitimate claim to power. This is not some transient or loosely committed population. Trump has built the first American mass political movement in the past century that is ready to fight by any means necessary, including bloodshed, for its cause.