Padlock Law

The law was extremely vague; it did not define Communism or Bolshevism in any concrete way. It denied both the presumption of innocence and freedom of speech to individuals. There were also concerns that the law would be used in order to arrest individual activists from international trade unions. Two union leaders were nearly arrested in that period. The law was used against Jehovah's Witnesses for distributing their publications, most commonly as a "prextext for search and seizure".

The federal government under Liberal Prime Minister William Lyon Mackenzie King could have used its power of disallowance to nullify the Padlock Law, as it had done to overturn equally controversial laws that had been passed by Alberta's Social Credit government around the same time. However, King chose not to intervene in Quebec.

The Supreme Court of Canada's 1957 decision in Switzman v Elbling struck down the law as ultra vires of the provincial government because it was an attempt by the province to enact a statute respecting criminal law, which is the exclusive domain of the federal parliament under the Constitution of Canada. In their concurrence, justices Ivan Rand, Roy Kellock and Douglas Abbott also argued the law was ultra vires because it contravened an implied bill of rights that underlies the Canadian constitution, but this view was not shared by the rest of the majority.