National Security

The U.S. Constitution divides responsibility for national security among the three branches of federal government. This system, known as the separation of powers, reflects the intent of the Constitution's framers that no single branch become too powerful. Thus each branch oversees the other through checks and balances with specific powers being neatly drawn. The president makes foreign policy through treaties with other nations, appoints ambassadors, and serves as the commander in chief of the armed forces. These executive branch powers are limited by those of the legislative branch. Congress imposes taxes to provide for defense, and the Senate ratifies the president's treaties and appointment of ambassadors before either can go forward. Although the president commands the armed forces, Congress alone may declare war. Overseeing these two branches is the judiciary. The courts' role is to see that they each exercise their own constitutional powers legally, without encroaching upon one another, while also safeguarding the civil liberties of citizens when they are threatened.

History, however, has blurred these neat lines. In the twentieth century, presidents have increasingly asserted control over national security in ways that have reduced the power of the legislative branch. Lawmakers have resisted this encroachment, yet with little success. The judiciary, for its part, has shown reluctance to intervene either to stop this trend or to uphold civil liberties that become captive to new definitions of the national interest. The practical conduct of national security thus has posed a hard question: who is in charge?

Congress and the president shared power comfortably until the Civil War. In 1861, President Abraham Lincoln took unprecedented action by ordering the blockade and capture of ships bound for Confederate ports, an action that brought a legal challenge by ship owners. They argued that he had exceeded his authority because Congress had not declared war. By a narrow 5-4 majority, the Supreme Court upheld the president's blockade in The Prize Cases (1862), named after an area of maritime law called prize law. The Court acknowledged that, even without a formal declaration by Congress, a state of war existed. Even though no branch of the government had the right to make war on one of its own states, laws passed in 1795 and 1807 gave the president the statutory right to suppress an insurrection. Decisions in this regard, the Court determined, belonged to the president, who could legally defend the nation without the need of action by Congress.