Bomarcs were supersonic, surface-to-air, long-range missiles capable of carrying nuclear warheads. They were designed and produced by the U.S. as anti-aircraft weapons to intercept and destroy Soviet bombers before they reached North America. For the system to be entirely effective, some of the missiles had to be installed at strategic locations in Canada.
In 1958, Diefenbaker hesitantly agreed to deploy 56 Bomarcs in Ontario and Québec. He made efforts to ensure they would only be employed for defensive action and that the Americans could not launch them without Canadian consent.
“The sole authority to authorize the use of those weapons in Canada would be the Prime Minister… who… would… give directions as to when and how they should be actually used.”