You are attending an executive seminar on National Security at an Ivy League university. Your cohort was broken up into different working groups. Your group consists of a DoD Senior Executive Service Director for Human Resources, two university professors, One Brigadier General from a European Nation, two civilian CEOs working in communications and logistics, an Ambassador from Canada, and you. Your group is tasked to identify challenges to NORTHCOM in the next five years. As the representative for the United States DoD, you are asked what the most significant threat to North America is. Using the National Security Strategic Guidance 2021 as a guide, what is your response to the group's