Canada was automatically entered into World War I when Britain declared war, and sent volunteers to the Western Front. Canada joined the 1919 League of Nations separate from Britain, but it was not until 1931, under the Statute of Westminster, that Canadian independence was affirmed. The fledgling country declared war on Germany three days after Britain in World War II.
In the 1960s, Quebec underwent the Quiet Revolution, which brought social and economic change. Quebecois nationalists began to press for a separate state, and established the Parti Quebecois. Two secession referendums were rejected, the first by a wide margin and the second much slimmer. The Canadian Supreme Court ruled unilateral secession by a province to be unconstitutional in 1997, but the movement for secession continues today.