“The Constitution has much to say to us regarding foreign policy, if we will only listen. For over half a century the two major parties have done their best to ignore what it has to say.”—Ron Paul

Since taking office, President Trump has escalated military involvement in Yemen. His administration ordered airstrikes targeting Iran-backed Houthi rebels, citing their attacks on shipping lanes in the Red Sea. These strikes have resulted in significant casualties, including civilians.

President Trump did not secure a formal declaration of war or any comparable congressional authorization for the military actions in Yemen. Does the Constitution allow the President to take military action unilaterally? There are some who say that the Constitution is ambiguous on the issue. Edwin S. Corwin in The President: Office and Powers, 1878-1957 has argued that the Constitution is a tussle for control between the executive and legislature. It is, he claims, “an invitation to struggle for the privilege of directing American foreign policy.”

I contend that Corwin is mistaken in proposing that the Constitution invites struggle. To the contrary, the text is clear and unambiguous in its support of legislative supremacy over the initiation of war. It indicates the following: 1) only Congress can initiate hostilities; 2) the President is limited to managing a war once it has been declared by the legislative branch; 3) the President’s authority to act without prior congressional approval is confined to imminent or sudden attacks. We find support for these statements in the historical record.

The Political Struggle over War Power

The war powers of Congress are contained in Article I, section 8. They extend to declaring war, raising and supporting armies, providing and maintaining a navy and making rules for the regulation of armed forces.

The President is given comparatively few explicit powers. He is commander-in-chief of the armed forces and of the state militias “when called into the actual Service of the United States.” It is the commander-in-chief function that has been the main source of tension between Congress and the Executive when it comes to formulating foreign policy.

There are, in American constitutional history, two competing viewpoints when it comes to deciding which branch ought to direct foreign policy. One argues in favor of executive dominance and the other in favor of congressional ascendancy. The former is associated with Alexander Hamilton, while the latter is attributed to James Madison. Madison condemned Hamilton’s support of an enlarged executive as monarchical, and consequently, inapplicable to the American situation. In this he was supported by Thomas Jefferson.

Ideas have consequences, and the seeds that Hamilton planted reaped their harvest in 1950 when President Harry Truman entered the US into the Korean War without congressional approval. Successive administrations have taken Truman’s precedent to its logical conclusion: the President can unilaterally send armed force wherever he wants, whenever he wants. The extent to which the executive branch has come to dominate foreign affairs is demonstrated by the stream of wars since World War II that have not been declared by the Congress.

Throughout the past seventy five years of presidential war-making, the judicial branch has remained ambiguous on where it stands. The Supreme Court has often refused to hear cases that directly pertain to war powers, citing the non-justiciable nature of the issues involved. This has forced many constitutional issues to be resolved in the political domain.

Initiation of War and the Historical Record

Historical evidence suggests the Constitution’s war powers were intended to be read in a way that strictly limits executive power. Expansive views of executive power were rejected by delegates to the constitutional conventions, and indeed by Hamilton himself. In Federalist Paper 69, Hamilton explained that:

[T]he president’s authority would be nominally the same with that of the King of Great Britain, but in substance much inferior to it. It would amount to nothing more than the supreme command and direction of the military and naval forces, as first general and admiral of the confederacy; while that of the British king extends to the declaring of war, and to the raising and regulating of fleets and armies; all which by the constitution under consideration would appertain to the Legislature.

The early presidents shared Hamilton’s judgment of the executive branch’s place in foreign policy. Take, for instance, Jefferson’s deployment of the navy to fight the Barbary states in response to attacks on US ships. “Recent studies by the Justice Department and statements made during congressional debate,” Louis Fischer writes in Presidential War Power, “imply that Jefferson took military measures against the Barbary powers without seeking the approval or authority of Congress. In fact, in at least ten statutes, Congress explicitly authorized military action.” President Lincoln was also a supporter of legislative supremacy. In opposing the Mexican War (1846-1848), Lincoln penned an eloquent defense of congressional initiative.

In the nineteenth century, it was even considered suspect if presidents tried to force Congress’s hand by maneuvering troops in ways that were likely to lead to war. President Andrew Polk amassed troops on the border with Mexico—an act consciously designed to intimidate the Mexicans into firing the first shot. As Senator John Middleton Clayton remarked at the time, “I do not see on what principle it can be shown that the President without consulting Congress and obtaining its sanction for the procedure, has a right to send an army to take up a position where, as it must have been foreseen, the inevitable consequence would be war.”

There is, however, likely one exception: defensive action designed to respond to an imminent or sudden attack. During the war against the Barbary powers, Jefferson understood that offensive maneuvering against the pasha of Tripoli had to be authorized by Congress, but defensive action was perfectly acceptable. Jefferson said that he was “unauthorized by the Constitution, without the sanction of Congress, to go beyond the line of defense.”

Supporters of war-making point to a State Department memorandum, which claims to find 87 instances prior to Truman in which presidents have waged undeclared wars. Yet, on closer inspection, the precedents turn out to be less persuasive than alleged. As Corwin himself observes in an essay for the New Republic in 1951, these examples mainly consisted of “fights with pirates, landings of small naval contingents on barbarous or semi-barbarous coasts, the dispatch of small bodies of troops to chase bandits or cattle rustlers across the Mexican border, and the like.” The military interventions of the 21st century can be distinguished from these sorts of minor deployments; presidents nowadays claim they do not need to seek any approval at all, despite being engaged in multiple large-scale conflicts of indefinite duration in areas far removed from America’s geographic region. So while it is true that, in some instances, presidents went to war without a declaration, Fisher reports that, in all cases until 1950, they sought congressional authorization after the fact.

Conclusion

In this article, I have critiqued Corwin’s view that neither Congress nor the President has a stronger legal claim to direct foreign policy. To label the Constitution in this manner implies that it does not contain a definite allocation of power over foreign policy. But the Constitution itself does not reveal any such ambiguity. The path forward lies in greater assertiveness by Congress with respect to its constitutional duties, unlikely though that may seem at present.