Help : Why was Canada willing to enter an air defense agreement with the United States?

The Cold War

—Because one of the main reasons that the Americans still wanted Canada in NORAD was the Anti-Ballistic Missile program (ABM). With the threat of bombers decreasing and the threat of intercontinental missiles increasing, NORAD needed to adapt to the new threats. The main issue was about where the ABM's would be located.

Both Canada and the US feared long-range Soviet attack. The Royal Canadian Air Force (RCAF) and the United States Air Force (USAF) would work together to ensure continental protection.

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its many islands, high mountains, and remote peninsulas isolated population centers.