“If Liberals Won’t Enforce Borders, Fascists Will.” So warned my colleague David Frum in the headline of an April 2019 article about America’s failure to control mass immigration. “Demagogues rise by talking about issues that matter to people, and that more conventional leaders appear unwilling or unable to address,” he wrote. “If difficult issues go unaddressed by responsible leaders, they will be exploited by irresponsible ones.” That thesis looked shaky in 2020. Voters declined to reelect