The Canadian military, like forces of other NATO countries, fought alongside the United States in most major conflicts since World War II, including the Korean War, the Gulf War, the Kosovo War, and most recently the war in Afghanistan. The main exceptions to this were the Canadian government's opposition to the Vietnam War and the Iraq War, which caused some brief diplomatic tensions. Despite these issues, military relations have remained close.
American defense arrangements with Canada are more extensive than with any other country.[92] The Permanent Joint Board of Defense, established in 1940, provides policy-level consultation on bilateral defense matters. The United States and Canada share North Atlantic Treaty Organization (NATO) mutual security commitments. In addition, American and Canadian military forces have cooperated since 1958 on continental air defense within the framework of the North American Aerospace Defense Command (NORAD). Canadian forces have provided indirect support for the American invasion of Iraq that began in 2003.[93] Moreover, interoperability with the American armed forces has been a guiding principle of Canadian military force structuring and doctrine since the end of the Cold War. Canadian navy frigates, for instance, integrate seamlessly into American carrier battle groups.[94]
In commemoration of the 200th Anniversary of the War of 1812 ambassadors from Canada and the US, and naval officers from both countries gathered at the Pritzker Military Library on August 17, 2012, for a panel discussion on Canada-US relations with emphasis on national security-related matters. Also as part of the commemoration, the navies of both countries sailed together throughout the Great Lakes region