According to Goldgeier and Saunders in "The Unconstrained Presidency," the set of political actors that have shown a declining capacity to constrain the president in the making of U.S. foreign policy are primarily Congress, the bureaucracy, and U.S. allies. Specifically:
- Congress has seen a decline in foreign policy expertise among its members and increasing political polarization, which has weakened its ability to supervise and constrain the executive branch on foreign policy matters.
- The bureaucracy has lost incentive and capacity to cultivate and wield expertise as decision-making has become more centralized in the White House, and congressional oversight has diminished.
- U.S. allies have become less able to check the president's foreign policies because the alliances have become entangled in U.S. partisan politics.
Overall, checks and balances intended to limit presidential power in foreign policy have eroded over decades, making it easier for presidents to act with greater unilateral freedom.
