Passage of the Volstead Act in 1920 expanded the mission of the U.S. Coast Guard. Law enforcement directives required officers to use "all necessary force" should a liquor smuggling vessel refuse the order to stop. On March 22, 1929, the Coast Guard Cutter Dexter sank the Canadian-flagged rum runner I'm Alone in the Gulf of Mexico, triggering an international incident that centered on "hot pursuit" and treaty jurisdiction. International encounters occurred frequently during Prohibition. The I'm Alone incident was the first sinking of a foreign flagged vessel that cost the life of a foreign national. The I'm Alone affair reflected the barriers any federal law enforcement agency faced in making Prohibition effective. The rum runner captain became a celebrity in Canada, while the Coast Guard was vilified. The Coast Guard amended boarding procedures after the incident cautioning officers about the possibility of accidental deaths.