Would NORAD exist in an isolationist United States?

Would NORAD still exist if the United States remained isolationist?

Some continental air-defence command probably would. Canadian cooperation might be less formal, but early interception and access to Alaska would still encourage it.

American air defence and the later binational form of NORAD are separate questions. An isolationist United States would still need to detect and intercept threats approaching North America. Cooperation with Canada remains strategically attractive because interception over Canadian territory is preferable to waiting until an attacker reaches the United States. Canadian access also supports reinforcement routes to Alaska. The organization might therefore have a different name or political structure, but geography still encourages a shared continental system.