Editor’s note: This article is part of the Just Security Symposium on Harold Hongju Koh’s “The National Security Constitution in the 21st Century”.
The authors would like to thank Taylor Booth and Marta Canneri, associates at Debevoise & Plimpton LLP, for their invaluable research assistance.
In his new book, The National Security Constitution in the 21st Century, Professor Harold Hongju Koh sets out two competing visions under the U.S. Constitution when it comes to the role of the branches of the U.S. government in the conduct of America’s foreign policy. On the one hand, balanced institutional participation among the three branches of government; on the other, a unilateralist Executive as the sole organ responsible for foreign affairs. Koh argues persuasively that the scales in recent years have tipped too far towards unfettered Executive unilateralism, in the face of a gridlocked legislature and a laissez-faire judiciary. Koh goes through the potentially serious reverberations of such unilateralism across a range of different issues, but we focus here on one that we have addressed before: the constitutional considerations in the “unmaking” of international agreements.
Whatever the debate may be regarding its contours, the U.S. Constitution explicitly requires some form of congressional participation for the United States to enter into most treaties and other binding international agreements (other than those that fall squarely within the president’s independent authorities over foreign relations). When it comes to how to exit such agreements, however, the U.S. Constitution is entirely silent. The practice in the last 20 years has trended—some might say aggressively so—toward Executive unilateralism in withdrawing from international agreements. And as we have previously argued, an assumed and unconstrained right of unilateral presidential withdrawal is problematic under constitutional law and in addition, destabilizing to international relationships.
One of the suggested structural solutions to the rise of Executive unilateralism is captured in what Koh refers to, and has previously referred to, as a “mirror principle” approach to withdrawal, which generally “requires for exit only the same degree of legislative participation as was required for entry.” We agree, but with some friendly modifications that we call a “tailored out” approach, which seeks to build in critical flexibility to address situations where the same level of congressional participation upon both entry and exit is unnecessary, impractical, or even unconstitutional. This approach adjusts as appropriate to the text and subject matter of the treaty or international agreement in question, considered in light of Justice Robert Jackson’s framework for scoping presidential powers in his Youngstown concurrence. Only then, as we detail below, can a new and more robust approach be grounded in a rigorous constitutionalism while simultaneously preserving flexibility to address the myriad different situations that may arise in practice.
Toward a New Approach to Withdrawal from International Agreements: A “Tailored Out”
The question of how to handle withdrawal from international agreements is not a new one. In Goldwater v. Carter, the Supreme Court faced the question whether President Jimmy Carter’s unilateral termination of a mutual defense treaty with Taiwan without congressional approval was constitutionally permitted. While the Court declined to resolve the issue as a non-justiciable political question, the situation prompted a flurry of scholarship and policy recommendations on alternative legal approaches to unilateral Executive withdrawal. Most notably, in 1979 the Senate Foreign Relations Committee proposed a resolution that would require congressional approval to terminate or suspend treaties except in certain specified circumstances, such as where material breach or other factors would give rise to a right of termination under international law. That resolution ultimately did not progress, but the underlying debate persists to this day.
When it comes to agreement making and breaking, we agree with Koh’s position that both “the degree of congressional approval” of the agreement in question as well as “the constitutional allocation of institutional authority over the subject matter at issue” must be considered. As we have argued, the President’s power to withdraw from international agreements exists on a continuum, like any presidential power. This reflects Jackson’s famous approach in Youngstown that presidential powers “are not fixed but fluctuate, depending upon their disjunction or conjunction with those of Congress.”
There is intuitive appeal to the clarity of the “mirror principle” for withdrawal, as it provides important certainty about the degree of legislative participation required: exit would “mirror” that of entry. Yet as Oona Hathaway’s meticulous scholarship has demonstrated, there is often no constitutionally sound rhyme or reason as to whether a particular agreement is entered into as: an Article II treaty, requiring the advice and consent of two-thirds of the Senate; a congressional-executive agreement, with either ex ante or ex post approval by a simple majority of both houses of Congress; or a sole executive agreement. The latter category is particularly dynamic, as it can be based on creative arguments regarding the scope of the president’s delegated or plenary powers.
To account for the various (and at times, arbitrary) manners in which the level of congressional participation may have been decided upon entry, our proposed “tailored out” approach is grounded in the subject matter of the treaty or international agreement in question in a more nuanced fashion driven by the context and circumstance in which the question arises. While Koh proposes recognizing the Executive’s authority to suspend agreements for a limited time in situations of “bona fide emergency,” we query whether every situation where the United States may need to act quickly to withdraw would rise to that very high threshold.
The “Tailored Out” in Action
Take, for example, the context of extradition agreements. These agreements are generally entered into as Article II treaties, meaning that approval of two-thirds of the Senate was required for “entry.” But extradition is a paradigmatic example of a subject matter where the Executive is entrusted under the constitutional system with independent authority over foreign affairs. Under the Youngstown framework—and as reiterated by the Supreme Court in Zivotofsky v. Kerry—to determine the scope of presidential powers, “the Court examines the Constitution’s text and structure, as well as precedent and history bearing on the question.” On that basis, the Supreme Court determined that in the field of diplomatic recognition, the Executive’s power starts with the Reception Clause in the Constitution, includes the president’s additional Article II powers to negotiate treaties and to nominate the nation’s ambassadors and dispatch other diplomatic agents, but also encompasses “functional” considerations such as the necessity for the United States to speak with “one voice” in international relations. Importantly, in coming to these conclusions, the Supreme Court noted that “[t]hough ratifying a treaty and confirming an ambassador require congressional approval, Congress lacks authority to initiate the actions without the President’s involvement.”
Of course, Zivotofsky did not deal with treaty withdrawal, but the underlying logic resonates here. So, for example, in the context of extradition, there is similarly a consistent assertion of Executive power as a matter of determining diplomatic relations with a foreign State, including an imperative to move quickly and with one voice. Thus, in contexts such as extradition, where the agreement may have been entered into as an Article II treaty but its subject matter does not fall within Congress’s sole authority, there is no good constitutional or practical reason to force an “out” that is the same as the “in.”
Take for another example the context of international trade agreements. Such agreements are typically entered into as congressional-executive agreements. Trade agreements tend to contain explicit withdrawal clauses, which may not require active congressional engagement to exit: this is less of a “mirroring” and more an exercise of adhering to the explicit text of the agreement. For example, in the U.S.-Mexico-Canada (USMCA) Trade Agreement, the withdrawal provision specifies that a party may withdraw “by providing written notice of withdrawal to the other Parties,” a step that the Executive plainly can take on the international plane without prior recourse to Congress. It is also the case that at least some congressional-executive trade agreements contemplate an ongoing role for Congress in their implementing legislation beyond express withdrawal provisions in the text of the agreement. For example, the implementing legislation for the agreement establishing the World Trade Organization provides an opportunity for Congress to vote on withdrawal every five years. In those instances, the “tailored out” approach would account for Congress’s exercise of its constitutional powers over international commerce in approving any withdrawal procedure in advance when authorizing the agreement, even if that procedure provides for an “out” that does not “mirror” the “in.” Again, this is not by virtue of the application of a bright-line rule, but rather a more nuanced assessment of the text and subject matter of a particular international agreement, considered in light of the Youngstown framework.
One benefit to this approach is that it still promotes restraint on Executive authority in “borderline” or otherwise controversial instances of unilateral Executive withdrawal, the prevention of which is an animating concern in Koh’s analysis. Take for example the congressional criticism around a recent trade agreement between the United States and Japan concerning critical minerals, which was concluded by the U.S. Trade Representative (USTR) without congressional approval, reportedly under delegated authorities contained in the USTR’s authorizing statute. A “mirror principle” would suggest the constitutionality of unilateral Executive withdrawal in that circumstance. But some members of Congress have criticized the agreement, arguing based on the Commerce Clause that the Executive does not have the authority to unilaterally enter into free trade agreements as a subject matter category. The “tailored out” approach would allow for more bespoke consideration of these particular instances, in support of a fettered Executive authority when it comes to withdrawal.
Consider also the Paris Agreement related to climate change, which Donald Trump has pledged to withdraw from—for a second time—if elected in November. Though the Paris Agreement was not approved by the Senate as an Article II treaty or by Congress as a congressional-executive agreement, the Agreement broadly implicates Congress’s commerce powers and, as Koh has previously noted, was “initiated by the executive with general congressional awareness and approval in a zone of congressional subject-matter authority based on a broader history of legislative authorization in a particular direction.” Indeed, the Paris Agreement, though nominally a sole executive agreement, was negotiated under the auspices of the U.N. Framework Convention on Climate Change (UNFCCC), an Article II treaty duly ratified with the advice and consent of the Senate. Further, there are no countervailing considerations that might weigh in favor of unilateral executive action, such as the need for a brisk exit or concerns about improper authorization. Accordingly, there is a strong basis for the point that Congress may not be excluded from the withdrawal process of the Paris Agreement, as an example of an agreement concluded with “considerable legislative input,” because doing so would impermissibly infringe upon congressional powers.
While we have in the past framed the “tailored out” as an alternative to Koh’s “mirror principle,” both approaches take inspiration from Jackson’s concurrence in Youngstown and are better understood as complementary. Viewing the two approaches together could allow for a framework in which a starting or at least relevant point could be the means of the “in,” while also permitting the “exit” to take account of more nuanced, fact-driven assessments of the allocation of constitutional authorities in line with Youngstown as well as the functional considerations highlighted in Zivotofsky.
Potential Congressional Reform
As Koh rightly points out in his recent work, structural checks to executive unilateralism are needed. As we have previously argued, Congress can clarify its role in the “unmaking” of international agreements by (i) baking conditions and requirements for withdrawal explicitly into the congressional authorization for a given agreement (informed by the Youngstown formulation and other constitutional considerations), and (ii) enacting legislation to set out a process for withdrawing from certain critical agreements or categories of agreements that are already in force. The Executive can also update its policy guidance by outlining the proper procedure for withdrawal in the State Department Foreign Affairs Manual (FAM).
One recent example of such an approach in practice is Section 1250A of the 2023 National Defense Authorization Act, which expressly prohibits the President from withdrawing from the North Atlantic Treaty Organization (“NATO”) or using any appropriated funds for that purpose without permission from Congress. As Scott Anderson has covered in detail, such a provision places any presidential withdrawal on the narrowest possible legal grounds and ensures that withdrawal would be scrutinized with caution by a reviewing court. As the North Atlantic Treaty is an Article II treaty adopted with two-thirds approval by the Senate, requiring congressional authorization for withdrawal places limitations on withdrawal that are consistent with the degree of authorization needed to enter the treaty. Such limits are also consistent with the subject matter of the treaty, which relates to the war powers shared between Congress and the president.
Concluding Thoughts
The question of presidential authority to withdraw from international agreements is of critical importance, especially in light of the upcoming 2024 presidential election. That election showcases a markedly different approach to the making and unmaking of international agreements between the two candidates. The previous Trump administration involved high-profile withdrawals and threats to withdraw from international agreements, including numerous seminal agreements and organizations such as the Paris Agreement, the Trans-Pacific Partnership, UNESCO, the World Health Organization, NATO, and the WTO. Trump’s recent public statements preview the potential for more withdrawals, for example regarding NATO, should his candidacy prevail. The practical and political stakes of this admittedly esoteric question of constitutional law are high, implicating as it does the effectiveness of the United States’ engagement and credibility with the international community, as well as promotion of consistency in U.S. foreign policy. Koh’s new book in this regard is an important and valuable charting of the potential path forward.