Anti-immigrant sentiment grew in response to fears of Bolshevik radicals and the deadly bombings by anarchists — the Islamic terrorists of their day. It reached a fever pitch in 1919 and 1920 with the Palmer Raids, the mass arrests and deportations of thousands of Eastern European immigrants. A key tool in those roundups had been the Espionage Act of 1917, which Hall’s IRL cofounder Charles Warren had drafted during a stint in government.