U.S. foreign policy and national security policies have significant domestic and international environmental impacts, and the increasingly precarious state of the global environment presents important new challenges to U.S. national interests. Day-to-day military operations, together with arms production, testing, deployment, and trade, are resource intensive and ecologically damaging. Although such activities are subject to growing environment-related legal and political constraints, most peacetime military activities and foreign operations are still not subjected to rigorous periodic environmental assessment.