The War Measures Act was a Canadian statute

Statute

A statute is a formal written enactment of a legislative authority that governs a state, city, or county. Typically, statutes command or prohibit something, or declare policy. The word is often used to distinguish law made by legislative bodies from case law, decided by courts, and regulations...

 that allowed the government to assume sweeping emergency powers in the event of "war, invasion or insurrection, real or apprehended". Enacted in August 1914, the act remained in force until being superseded by the Emergencies Act

Emergencies Act

The Emergencies Act is an Act of the Parliament of Canada to authorize the taking of special temporary measures to ensure safety and security during national emergencies and to amend other Acts in consequence thereof....

 in 1988.

The act was invoked three times in Canadian history: during the First World War, the Second World War, and the 1970 October Crisis

October Crisis

The October Crisis was a series of events triggered by two kidnappings of government officials by members of the Front de libération du Québec during October 1970 in the province of Quebec, mainly in the Montreal metropolitan area.The circumstances ultimately culminated in the only peacetime use...

 and, when used, is often seen as being in opposition of Canadian rights and freedoms.
The War Measures Act has been questioned about its suspension of civil liberties and personal freedoms, most notably during the Japanese Canadian internment

Japanese Canadian internment

Japanese Canadian internment refers to confinement of Japanese Canadians in British Columbia during World War II. The internment began in December 1941, following the attack by carrier-borne forces of Imperial Japan on American naval and army facilities at Pearl Harbor...

 and October Crisis

October Crisis

The October Crisis was a series of events triggered by two kidnappings of government officials by members of the Front de libération du Québec during October 1970 in the province of Quebec, mainly in the Montreal metropolitan area.The circumstances ultimately culminated in the only peacetime use...

.