We at Duke University are initiating a year-long project in which a number of us will be considering and discussing the relationship between law and custom. In connection with that project, I have started thinking about the role of historical practice in debates over separation of powers, including in debates over the Constitution’s distribution of war authority.
There are two basic positions on the constitutional distribution of war powers – a pro-Congress view and a pro-Executive view. Although it has some variants, the pro-Congress view generally contends that the President is constitutionally required to obtain congressional authorization for the use of military force except when defending the United States from attack or protecting the safety of U.S. citizens abroad. The pro-Executive view, by contrast, contends that the President may use military force abroad without congressional authorization, and that Congress’s ability to check the President stems primarily from its control over appropriations.
The military operations in Libya have once again triggered a substantial debate over war powers. The positions in this debate are illustrated by, on the one hand, an opinion from the Office of Legal Counsel, and, on the other hand, an essay critiquing the opinion by Professor Michael Glennon. As is evident from these materials, debates over war powers are often in part debates over the interpretation and weight to be given to historical practice — in particular, the instances in which presidents have initiated the use of military force without congressional authorization. The OLC opinion on Libya, for example, recites various instances of “such presidential initiative,” whereas Glennon argues that many of these instances are distinguishable.
In thinking about the Libya debate, I’ve started to have greater doubts, or at least uncertainties, about the proper role of historical practice in constitutional interpretation relating to the separation of powers. The best case for relying on this practice would be in circumstances in which it is clear that the political branches have come to an understanding over time that a certain arrangement is permissible. (A possible example is the Senate’s longstanding assertion of authority to condition its advice and consent to treaties with reservations, a practice dating almost back to the Founding and accepted by presidents.) The war powers context, however, reveals that it is often difficult to know when such a shared understanding exists.
Sometimes presidents seek congressional authorization for war – for the conflicts in Vietnam, Afghanistan, and Iraq, for example. Sometimes when they do not do so there are plausible arguments that the President is exercising some sort of narrow war authority, relating, for example, to the protection or rescue of U.S. citizens abroad. At other times, substantial opposition is voiced in Congress even though no formal bill of disapproval is passed, which is what happened with respect to the Kosovo bombing campaign. Sometimes Congress may decide not to oppose a particular operation for ad hoc political reasons rather than a general understanding of presidential authority.
Supporters of both the pro-Congress view and the pro-Executive view invoke the War Powers Resolution of 1973, but its implications for any sort of shared understanding are unclear. On the one hand, it states in Section 2 that the President has the authority to use force only upon either “(1) a declaration of war, (2) specific statutory authorization, or (3) a national emergency created by attack upon the United States, its territories or possessions, or its armed forces.” On the other hand, presidents have indicated at various times that they do not agree that this is a correct description of the Constitution. Section 5 of the War Powers Resolution calls for termination of presidential uses of force after 60 days unless approved by Congress, which might suggest that Congress accepts the constitutionality of presidential uses of force of shorter duration. On the other hand, it may simply suggest that Congress compromised on the remedy it mandated for illegal operations, especially if this section is read in conjunction with what is stated in Section 2. Finally, Section 8 of the Resolution states that the authority to use force shall not be inferred from treaties. On the other hand, presidents have subsequently relied on treaties as partial justification for the use of force, including in the Libya campaign.
What is the upshot of all this? If nothing else, it seems to me that if one is committed to the pro-Congress view of war powers for other reasons – because, for example, it appears to best represent the original constitutional understanding – historical practice does not provide a convincing reason to alter this commitment. More broadly, it may be that constitutional claims based on practice are made too readily in a variety of contexts and that we need to think more deeply about when and why this practice should matter.