What is the primary legal distinction between 'national security' and 'homeland security' activities?

The primary legal distinction lies in the focus and permissible targets of the activities. National security activities primarily concern protecting the nation from external threats, often involving actions taken outside U.S. borders and targeting foreign entities or governments. These actions are typically governed by laws related to foreign intelligence, military operations, and international relations. Homeland security activities, on the other hand, focus on protecting the nation from threats within its borders, including terrorism, natural disasters, and other emergencies. These activities are generally governed by domestic laws related to law enforcement, emergency management, and infrastructure protection, and they are constrained by constitutional protections afforded to individuals within the United States. For example, surveillance conducted for national security purposes may be subject to different legal standards than surveillance conducted by domestic law enforcement for homeland security purposes, especially concerning U.S. citizens. The key difference is the legal framework that governs the actions, based on whether the primary target and location of the activity are foreign or domestic.