American foreign policy since 1945 has rested on permanent alliances, forward-deployed forces, and periodic intervention. Each element is now openly contested across the political spectrum rather than along it.
Treaty alliances such as NATO commit members to collective defense. Supporters describe this as the foundation of a long peace among major powers; critics describe it as an open-ended commitment made under different conditions.
Intervention takes many forms short of war: sanctions, arms transfers, intelligence sharing, training, and limited strikes. Each carries different costs, escalation risks, and legal authorities.
The constitutional allocation of war powers between Congress and the executive remains unsettled in practice. Force has repeatedly been used under decades-old authorizations or claimed executive authority without new congressional votes.