The Marijuana Tax Act of 1937 was passed with little fanfare. Many legislators were unsure exactly what marijuana was, and there was minimal debate leading up to the floor vote. Sociologist Howard Becker attributed this law to the moral entrepreneur-ship of Harry Anslinger, the long-standing head of the Federal Bureau of Narcotics, who promoted marijuana as a threat to public safety and luridly linked the drug with Mexican immigration into the Southwest. (The Federal Bureau of Narcotics was the precursor to the Drug Enforcement Administration.)