On June 25, 2021, the Acting Assistant Secretary of Defense for International Security Affairs, Dr. Mara Karlin, hosted the 239th meeting of the U.S.-Canada Permanent Joint Board on Defense (PJBD). Started in 1940, the PJBD is a critical forum for U.S.-Canada bilateral defense cooperation, which brings together key leaders to discuss bilateral defense issues and overall defense priorities. Dr. Karlin, the acting U.S. co-chair of the PJBD, and the Honorable John McKay, the Canadian co-chair, convened a virtual meeting of the PJBD to discuss North American Aerospace Defense Command (NORAD) modernization and the benefits of consulting during the development of strategic defense guidance. The PJBD reviewed a framework to guide NORAD modernization efforts to improve capabilities necessary for NORAD to conduct its aerospace and maritime warning and aerospace control missions. The co-chairs re-affirmed the importance of the U.S.-Canada defense relationship and the need to deepen collaboration on areas of mutual defense and security interest.