If Trump’s opponents stand opposed to policing America’s boundaries, they will not help immigrants—they will only lose votes. DAVID FRUM 10:32 AM ET [Cut] For Trump’s opponents, the caravan represents a trap. Has Trump’s radical nativism so counter-radicalized them that they have internalized the caravan message against any border enforcement at all? If yes, they will not help immigrants. They will only marginalize themselves—and American politics will follow the European path in which anti-immigration parties of the extreme right cannibalize the political center. If liberals insist that only fascists will defend borders, then voters will hire fascists to do the...