United States military bases in Latvia and Lithuania support European troops in countering Russian aggression

Study and practice of how sovereign states, international institutions, and non-state actors interact across borders. Encompasses diplomacy, negotiation, alliances, and conflict — the foundational domain through which global order is constructed, contested, and maintained.

The goals, strategies, and diplomatic, economic, and military tools through which the United States engages other states and international institutions, including alliances, sanctions, aid, and the use of force.