Armed Conflict Congress

May Congress Delegate Its War Power?

Matthew Waxman
Wednesday, January 10, 2024, 9:21 AM
The constitutionality of congressional delegation of war power was highly contested for much of American history. Would war powers reform restore Congress’s original authority?
President Woodrow Wilson asking Congress to declare war on Germany in 1917. (Library of Congress)

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War powers reform is a hotly debated topic these days, and so are the constitutional limits of legislative delegation. Recently, Michael Ramsey, of the University of San Diego, and I set out to study the intersection of the two issues: Now that—since World War II—Congress no longer formally declares war but instead, in the case of all major U.S. ground wars since Korea, sometimes authorizes the president to use military force, what can we learn by considering force authorizations as legislative delegations—essentially, delegating vast policy discretion to the president as to whether and when to go to war, or perhaps not to use any force at all? Among other issues, we were interested in when and how this practice became so well accepted that even most critics of presidential unilateralism see it as constitutionally satisfactory. 

To the extent that congressional force authorizations are thought about as delegations of some exclusive congressional war power (and reasonable lawyers may disagree on where the boundary of that exclusive power lies), there are two common approaches that pull in completely opposite directions. 

One takes the—now more common—view that broad legislative delegations are especially permissible with regard to foreign affairs (per Justice George Sutherland’s opinion in United States v. Curtiss-Wright), and going to war is a quintessential foreign affairs issue. Therefore, whatever exclusive power Congress may have to initiate war, it is exceptionally delegable. The other, with a long pedigree throughout American history, takes the view that there are grave and particular stakes and risks associated with war and presidential decisions to wage it. For that reason, this specific congressional power is exceptionally, maybe uniquely, nondelegable. Both approaches see war power as special, but in antithetical ways. 

In a recent article, we trace the history of constitutional debates and practices of war power delegation, and we discuss implications for contemporary conversations about nondelegation in “foreign affairs,” as well as for war power reform. We show that the history of war power delegation does not provide strong support for either of the two common but opposite positions mentioned above. 

From the Constitution’s earliest years until the mid-20th century, war-initiation delegations were rare and typically specific and conditioned on particular events. Broad delegations became more common only after World War II, in response to geostrategic imperatives of the Cold War, but also, importantly, against a background expansion in the exercise of unilateral presidential power to use force. Controversies over the latter trend overshadowed concerns about war power delegation, and many legislators who accepted vast presidential war powers for the most part didn’t think they were delegating anything. A key period for this Cold War development was the Eisenhower administration, when Congress passed a pair of resolutions that essentially authorized war to protect, respectively, Formosa and the Middle East from aggression. In neither case did the president act on the resolution. Overall, we argue that the historical record counsels against treating “foreign affairs delegations” as a single category, and it reveals that constitutional questions of how Congress exercises war power have over the long run been as significant as whether it has done so.

The article is largely historical, but it is not an originalist-doctrinal argument for or against the constitutionality of broad war power delegation. War power delegation might be defended or opposed constitutionally on functional grounds, for example, and the article details some associated specific strategic considerations and challenges. For instance, war power delegation was sometimes seen as an important tool for enhancing the credibility of commitments to foreign allies or partners. Although we don’t ourselves take a firm doctrinal position on the constitutional limits on war power delegation, the historical record is nevertheless relevant in several ways to contemporary debates about war power. 

For one, a defining feature of American constitutional war powers is the extent to which, even centuries after the founding, many basic legal questions remain hotly contested, and the extent to which partisans in strategic debates over the use of military force wield constitutional arguments for political effect. It is therefore not so surprising, for example, that whereas war power nondelegation objections were muted at the beginning of the Vietnam War, they more loudly accompanied political opposition to that war, and to military interventionism more generally, in the 1970s. 

That point about the politics of constitutional war power arguments is especially worth highlighting at this moment because U.S. overseas military commitments currently face opposition from both the right and the left. The historical record suggests that we will likely see an uptick in war power nondelegation arguments again as a tool of resistance to perceived military adventurism—whether in the context of ongoing counterterrorism campaigns, or possible future ones, like legislative proposals to grant the president wide discretion to use military force against drug cartels—and at a time when the nondelegation doctrine generally seems to be in some flux.

The historical record also reveals that some of the most open-ended congressional delegations of war power were intended not simply to deal with a familiar legislative challenge of managing complexity but also to address a particular strategic challenge of bolstering the credibility of threats of force or international security institutions. Patrick Hulme and I recently wrote in Lawfare about the challenges of squaring war power reform with credible alliance commitments. We explained that one way to combine exclusive congressional war power with very strong alliance commitments might be for Congress to legislate standing force authorizations to protect allies from attack—and that this idea received a lot of attention when Congress enacted the 1973 War Powers Resolution—but that we see this idea as unrealistic and problematic. It is unrealistic because a Congress trying to claw back its war power would be unlikely to turn around and broadly delegate it. It would be problematic, among other reasons, because efforts to implement it would likely leave some allies out in the cold, thereby worsening the credibility of assurances. The historical record of war power delegations nevertheless suggests that the policy imperative of credible threats was a powerful driver of this practice.

Finally, the history of constitutional objections to war power delegation is also relevant to contemporary debates about war power reform. Reformists often pitch their calls as “restoring” or “reclaiming” Congress’s original constitutional role in war initiation, but the historical record reveals early and recurring congressional debates about how Congress was permitted to exercise its war power. It is not clear, for example, that a forward-looking delegation of authority to use force would have satisfied constitutional requirements for how Congress exercised its exclusive war powers at the founding. 

Whereas, today, requiring an express congressional force authorization for any major hostile use of armed force is generally seen as fully restorative of Congress’s original war power, our findings complicate whether this requirement would represent a genuine restoration, or something different altogether. The early understanding of Congress’s war power was in fact highly contested—not contested in the way commonly discussed, as a dispute over whether Congress’s powers were exclusive, but contested as to how Congress was required to exercise those exclusive powers. Peeling back presidential unilateralism exposes delegation issues lurking beneath. Those advocating a reversion to exclusive congressional war power should therefore also grapple with whether there are any constitutional limits to its delegation.

Matthew Waxman is a law professor at Columbia Law School, where he chairs the National Security Law Program. He also previously co-chaired the Cybersecurity Center at Columbia University's Data Science Institute, and he is Adjunct Senior Fellow for Law and Foreign Policy at the Council on Foreign Relations. He previously served in senior policy positions at the State Department, Defense Department, and National Security Council. After graduating from Yale Law School, he clerked for Judge Joel M. Flaum of the U.S. Court of Appeals and Supreme Court Justice David H. Souter.

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