In one short, succinct statement Justice George Sutherland altered the relationship between Congress and the executive branch. “The President [operates] as the sole organ of the federal government in the field of international relations,” he wrote in the United States Supreme Court’s decision of U.S. v. Curtiss-Wright Export Corporation. Whereas the Constitution lays out distinct, delegated powers to Congress, such as the power to declare war and the power to ratify treaties, and to the executive, primarily the role of the president as Commander-in-Chief, Justice Sutherland’s statement altered the relationship between the two aforementioned branches. Suddenly, the executive branch had a legal precedent with which to become the leading force in foreign policy and upon which it could fall back on if actions are legally challenged.

The judicial branch’s role is often underappreciated in foreign policy, primarily because its forays into the field of international relations are relatively uncommon. That does not mean, however, the judicial branch does not serve a crucial role in foreign policy. In fact, it is the judicial branch that serves as the one true restraint upon the executive branch. While Congress can attempt to restrain the executive branch through laws or procedural technicalities, it is often unsuccessful.

For instance, Congress had a revival of sorts following the disastrous Vietnam War and the embarrassing Watergate scandal. Both events, displaying the centralized power the executive branch had attained since the World War II, spurred Congress to take action to restrain the branch and to insert Congress into a more prominent role in foreign policy. The primary example of this is the War Powers Resolution, which requires presidents to inform Congress of the use of the military in any conflict around the world. Its intent was to prevent a president from heavily investing the U.S. military in another conflict like Korea or the Vietnam War. Despite not having a declaration of war from Congress, the U.S. military was fully engaged in those two conflicts. However, the War Powers Resolution had been more bark than bite. President Ronald Reagan, President George H.W. Bush, and President Bill Clinton all deployed troops in various conflicts and countries around the world as they saw fit. Sure, each president had to report their use of the military to Congress, but it did not restrain them and it certainly did not deter them from using the military.

The distinct powers delegated to each branch with regards to foreign policy provides for a lot of grey area. As noted above, presidents have deployed troops as they see fit with little or on advice from Congress. In fact, according to a 2001 memo from the Department of Justice, presidents, including George Washington, authorized military action 125 without expressed consent from Congress. This grey area allows presidents to expand and to push the limits of their constitutional authority. Congress can do little other than attempting to implement ineffectual restraints on the president. But as seen after 9/11, Congress could do little about the growth in presidential power seen under President George W. Bush, specifically actions taken in the War on Terror, and currently under President Barack Obama, such as the increased use of drones in the War on Terror.

However, the judicial branch, specifically the Supreme Court, can take binding actions that curb executive power. In the 2004 case Rasul v. Bush, the Court ruled the U.S. court system does have the authority to determine if foreign nationals were wrongfully detained, despite claims to the contrary by the Bush administration. Two other Bush-era cases also demonstrate the power of the judicial branch. In Hamdi v. Rumsfeld, the Court ruled U.S. citizens have the right to challenge their status as an enemy combatant in court and in Hamdan v. Rumsfeld,  the Court ruled the Bush administration’s use of military commissions to try detainees at Guantanamo Bay was unconstitutional.

Supreme Court rulings do not allow for wiggle room, unlike actions taken by Congress. The executive branch must abide by the decisions of the Supreme Court, even if the administration in power disagrees with a particular ruling. Thus, the judicial court is indeed the one true restraint on the executive, which is ironic considering it was a justice’s statement that provided a legal precedent for the executive branch to centralize foreign policy power and take unilateral action without congressional consent.