William Lyon Mackenzie King continued in power after the war, retiring in 1948 as Canada’s longest-serving prime minister. His Liberal Party stayed in power until 1957. During this period Canada moved toward vigorous federal intervention in the economy, following the theories of British economist John Maynard Keynes, who proposed that government spending should be used to create jobs when business investment was insufficient. Job creation and prosperity became state commitments, and many new social programs such as tax incentives, veterans’ benefits, and family allowances (support payments to families with children) were introduced. The way had been paved for public acceptance of these programs during the war, when the federal government had begun some of them under its sweeping authority for wartime economic measures.