Louis Stephen St. Laurent PC CC QC was a Canadian politician who served as the 12th prime minister of Canada, from 15 November 1948 to 21 June 1957. He was a Liberal with a strong base in the Catholic francophone community, from which base he had long mobilised support to Prime Minister William Lyon Mackenzie King. St. Laurent was an enthusiastic proponent of Canada's joining NATO in 1949 to fight the spread of Communism, overcoming opposition from some intellectuals, the Labor-Progressive Party, and many French Canadians. The contrast with Mackenzie King was not dramatic – they agreed on most policies. St. Laurent had more hatred of communism, and less fear of the United States. He was neither an idealist nor a bookish intellectual, but an "eminently moderate, cautious ... man ... and a strong Canadian nationalist".