The U.S.-Ukraine Security Agreement Is What the Parties Will Make of It

On June 13, President Joe Biden and Ukrainian President Volodymyr Zelenskyy signed the U.S.-Ukraine bilateral security agreement. According to the White House, the 10-year agreement is intended, among other things, to “build and maintain Ukraine’s credible defense and deterrence capability,” “accelerate Ukraine’s Euro-Atlantic integration,” and “achieve a just peace.” Zelenskyy, in turn, called it the “strongest agreement between Ukraine and the U.S. since [Ukraine’s] independence.” In short, both the Biden and Zelenskyy administrations present the agreement as a show of strength and unity to the Kremlin and the rest of the world, that with the United States’s help, Ukraine will have sufficient military capabilities necessary to defend itself from and deter Russian armed attacks now and in the years to come.

Not everyone takes this view, however. In a recent Lawfare piece, Harvard Law Professor Jack Goldsmith emphatically challenged this view, pointing out that commitments outlined in the agreement actually send “something approaching the opposite” of the intended message to Russia. “It demonstrates the Biden administration’s and the United States’s surprisingly weak commitment and resolve in defending Ukraine against Russian aggression,” he wrote. 

I share many of Goldsmith’s critical observations about the current state of the agreement, as I explain in this piece. However, the agreement does have the potential to significantly contribute to creating a strong U.S.-Ukraine security cooperation capable of deterring Russia—it just needs to be further developed and formalized to increase chances of its proper implementation and financing. And in its current form, the agreement—while not likely sending the intended message to the Kremlin—notably does not signal the lack of U.S. resolve, either.

A Hybrid Legal Form and Doubts About Zelenskyy’s Treaty Powers

The U.S.-Ukraine agreement contains language indicating that it is a binding treaty under international law. For example, the agreement refers to the U.S. and Ukraine as “parties” and uses the term “entry into force”—a phrase the International Court of Justice (ICJ) used to identify the presence of a treaty in Somalia v. Kenya. In addition to this language, the agreement stipulates the parties’ intention to register it in the United Nations, which may also signal their intention to have a legally binding agreement.

Still, simply because an agreement is binding does not mean that it cannot also contain nonbinding provisions. For instance, most provisions outlined in the U.S.-Ukraine agreement are framed as “policies” or “intentions” (notably, not commitments) of the United States. Also, an annex to the agreement (with many consequential U..S commitments described below) is explicitly nonbinding, providing that nothing in it “gives rise to rights or obligations under domestic or international law.” Indeed, following the signing of the agreement, Zelenskyy mentioned that the agreement contains a “legally binding part” (emphasis added). President Biden did not object. What’s more, a fact sheet published by the White House shortly after the two leaders signed the agreement acknowledged that it includes “binding commitments.”

That said, as Goldsmith pointed out, the agreement “appears to be an executive agreement—within the meaning of U.S. law—made solely on [President Biden’s] authority” (emphasis added). There seems to be no serious doubt about the American president’s authority to make such an agreement in accordance with U.S. law under Article II of the U.S. Constitution. The same cannot be said of Zelenskyy’s presidential authority in Ukraine.

Under Ukrainian law, there are serious doubts about whether the president can conclude this type of legally binding international agreement without ratification by Verkhovna Rada—the Ukrainian parliament. More specifically, Article 9(2) of the Law of Ukraine on International Treaties requires parliamentary ratification of “political treaties,” which include treaties on “mutual assistance and cooperation” (emphasis added). The law’s requirements are binding on the president under the Ukrainian Constitution. The fact that the U.S.-Ukraine agreement covers mutual security as well as political assistance and cooperation (for example, Ukraine committed to sharing intelligence with the United States), and that this agreement is of extremely high salience for Ukraine, creates a compelling argument that the agreement must be ratified by the Verkhovna Rada. Considering the absence of specific Ukrainian court practice on this issue, one might try to undermine the need for Verkhovna Rada ratification by arguing that it relates primarily to security (not simply political cooperation) or deals largely with U.S. security assistance. In my view, that would not be the best reading of the law, considering its broad language providing for the ratification of “mutual assistance and cooperation” agreements without exceptions. That said, Zelenskyy’s party holds the majority in the Verkhovna Rada, so it’s unlikely that the parliament will push back against the agreement. Still, the situation creates some uncertainty about the proper expression of Ukraine’s consent to participate in an international agreement, and whether that agreement is binding under Ukrainian law.

What’s more, there is an important caveat to consider regarding Ukraine’s apparent legal obligation under Article IV of the agreement to “undertake efforts” to implement widespread reforms, including in the judiciary, anti-corruption, and defense spheres. According to the Law on International Treaties, any treaty involving the enactment or amendment of laws is subject to parliamentary ratification. That means that without ratification by the Verkhovna Rada, President Zelenskyy could have potentially agreed only to Ukraine’s reforms not involving legislative changes. Since Article VII of the agreement specifies that any cooperation thereunder takes place in accordance with domestic law, Ukraine’s reform efforts under Article IV are therefore likely limited to activities that do not entail the adoption of laws, such as presidential actions to promote reforms. The broader interpretation of this provision would run contrary to a fundamental norm of Ukrainian law on the parliament’s exclusive legislative powers and thus would create potential risks of invalidating Ukraine’s consent to the agreement under Article 46 of the Vienna Convention of the Law of Treaties.

Agreements with Ukraine’s other partners do not raise similar concerns because all of them contain significant signs of political agreements.

Context

Despite its shortcomings, the agreement is a significant step forward in U.S.-Ukraine relations. In this respect, Zelenskyy was correct when he said that this is the strongest security agreement ever reached between the two countries.

Following the Soviet Union’s collapse, Ukraine relinquished its nuclear weapons and joined the Treaty on the Non-Proliferation of Nuclear Weapons as a non-nuclear state in exchange for, among other things, shallow security commitments from the United States, the United Kingdom, and Russia set forth in the ambiguous Budapest Memorandum (see details on its design in my earlier Lawfare piece). The memo’s signatories, among other things, promised to “respect the independence and sovereignty and existing borders of Ukraine” and conduct consultations in case “a situation arises which raises a question regarding [the] commitments.” U.S. officials also reportedly orally promised Ukraine to take a strong interest and respond in the event that Russia violates the memorandum. It remains unclear whether this response was meant to include military assistance, which, according to former U.S. Ambassador to Ukraine Steven Pifer, it should. 

The Budapest Memorandum’s weak commitments and related security gap came back to bite Ukraine during the start of Russia’s aggression in 2014 with its occupation of Crimea and invasion of the Donbas via its proxy forces with the direct support of the Russian regular army units. Then, despite bipartisan support and authorization from Congress, the Obama administration decided not to provide Ukraine with the support necessary to defend itself, including lethal weapons. Rather, the Obama doctrine took the position that “Ukraine is a core Russian interest but not an American one, so Russia will always be able to maintain escalatory dominance there.” Accordingly, the U.S. response was largely limited to nonlethal security and other assistance to Ukraine (for example, body armor, radars, night-vision devices), relatively restrained sanctions, and public and diplomatic condemnations of Russia, which the Obama administration considered to be enough to honor the United States’s security commitments to Ukraine under the Budapest Memorandum. Only much later, in December 2017, did the Trump administration make a decision to provide limited lethal assistance such as Javelin anti-tank missiles. Also, at the beginning of Russia’s 2022 full-scale invasion of Ukraine, analysts expressed doubts that the U.S. would provide the military and economic support needed to fight back against the Russian attacks. It was only after Ukraine successfully resisted initial Russian attacks that the United States and other allies came up with the necessary assistance.

Against this background, the U.S.-Ukraine agreement formalizes the policy and related commitments to maintain Ukraine’s defense and deterrence capabilities, including the long-term provision of substantial lethal assistance that was taboo for U.S. policy for many years before the full-scale invasion. Now, it’s the default course of action. While the agreement is an important development, its ultimate success requires significant improvements combined with proper implementation and financing. 

The North Atlantic Treaty or other similar security obligations that provide for the potential direct support of allied forces in armed conflict are not the best comparison for assessing the U.S.-Ukraine security agreement. Indeed, the intended security framework for Ukraine is envisioned as an interim substitute for NATO. Rather, the U.S.-Ukraine security agreement is modeled in part after the U.S.-Israel security arrangements that ensure Israel’s defense and deterrence capabilities by maintaining its “qualitative military edge” over neighboring militaries.

Importantly, U.S participation is a crucial element of the framework of more than 20 other bilateral security agreements Ukraine signed with other Western partners. Indeed, on the sidelines of the 2024 NATO summit in Washington, D.C., President Zelenskyy and leaders of these partner nations, including President Biden, endorsed the Ukraine Compact connecting the agreements into one framework. Therefore, the success of the U.S.-Ukraine agreement is also closely connected to the success of these other agreements because the partners share their responsibilities in ensuring Ukraine’s defense and deterrence capabilities.

What’s more, the U.S.-Ukraine agreement comes amid an unpredictable war with Russia. The ongoing nature of the war increases the risk that the United States’s and Ukraine’s goals may not (and likely will not) always be the same. Thus, as explained below, the agreement—in its current state—should be treated as a “living document”—one that can be altered, updated, and improved as circumstances evolve. 

Key Provisions

Against this background, the following general parameters of the U.S.-Ukraine security cooperation, even when framed as intentions or political commitments rather than legal obligations, are now defaults in U.S. policy toward Ukraine’s security. Below is a comprehensive summary of the agreement’s key elements, and suggestions for how they can be improved in the future.

Standard of Support

Article II of the agreement defines a standard of American support to Ukraine as “credible defense and deterrence capability.” This sets a benchmark for assessing future American military support to Ukraine. While this standard is framed as a U.S. policy (not an obligation) in the main text, the agreement’s annex features more committal language, including the political commitment made by the U.S. to “support Ukraine in developing modern, NATO-interoperable force that can credibly deter and, if necessary, defend against future aggression” (emphasis added).

To make this commitment more concrete and thus more credible, the parties should develop detailed criteria of this standard against which the support to Ukraine can be measured. For example, one of these elements could be framed along the following lines (based in part on the example of Israel’s qualitative military edge):

Ukraine’s ability to counter and repel any conventional armed attacks from Russia, while sustaining as lowest as possible damages and casualties, by having the sufficient quality and quantity of military means, including weapons, command, control, communication, intelligence, surveillance, and reconnaissance capabilities, to offset or match Russia’s battlefield advantages.

Separate criteria for each of Ukraine’s various capabilities in relation to Russian ones—including that of artillery, armor, air power, and defense—could be further developed, for example, within the “capability coalitions” in the Ukraine Defence Contact Group..

The current wording of the standard, however, is too broad to measure what capabilities Ukraine is lacking at each particular point in time. It’s also important to agree on regular assessment procedures to make sure the support is in fact calibrated to meet the criteria.

The U.S. commitment to Israel’s qualitative military edge is a good example of how this can be done. Notably, unlike the U.S.-Ukraine agreement, the nonbinding U.S.-Israel memorandum of understanding does not contain a defined standard for American support. The qualitative military edge standard was instead codified in U.S. law in the 2008 Naval Vessel Transfer Act, which serves as a baseline for the president to make repeated assessments of Israeli capabilities. However, this happened only after many years of informally applying this standard in U.S.-Israel security relations. The U.S.-Ukraine agreement already contains the credible defense and deterrence capability standard and, like that of Israel, offers a starting point for further development and formalization, including (potentially) codification in U.S. law.

On a separate note, unlike agreements between Ukraine and some other partners (for example, the U.K., France, and Italy), the U.S. agreement contains neither U.S. policy nor commitment to ensure Ukraine’s capabilities necessary to fully restore its territorial integrity. The U.S.-Ukraine agreement provides only that commitments in it are “intended to support Ukraine’s efforts to win today’s war[.]” However, there is no U.S. commitment to work to ensure the respective Ukrainian capabilities (unlike security agreements with some other partners), and the term “win” may mean different things for Ukraine and the United States.

That said, there may be disagreements between Ukraine and some other partners about what level of future Ukrainian capabilities is appropriate. However, the partners’ agreement on the “credible defense and deterrence capability” standard in the Ukraine Compact suggests that it is considered as a floor (but not a ceiling) of their support.

Means of Support

In his Lawfare piece, Goldsmith correctly pointed out that the provision of “substantial levels of security assistance for Ukraine” is framed as a policy rather than an obligation and that the U.S. only intends to seek relevant appropriations from Congress. It’s important to note here that the agreement’s annex also provides the United States’s intent “to provide long-term material, training and advising, sustainment, intelligence, security, defense industrial, institutional, and other support to develop Ukrainian security and defense forces that are capable of defending a sovereign, independent, democratic Ukraine and deterring future aggression.” This intent should be considered alongside the United States’s aforementioned political commitment to support relevant Ukrainian capabilities. The annex also details the United States’s intention to beef up Ukrainian capabilities in various domains, including air and missile defense, fire, ground maneuver, air, and maritime. This provision is relatively detailed—the U.S. made various political commitments within each of these categories. For example, the U.S. committed “to support Ukraine’s development of a layered, integrated air and missile defense system” and to “support Ukraine’s development of a joint fires capability, to include the acquisition of ground-based systems, munitions, and targeting capabilities to employ indirect and long-range fires, as well as unmanned aerial systems.”

That said, the absence of concrete, qualitative figures is indeed a significant drawback of the U.S.-Ukraine agreement compared to the nonbinding 2016 U.S.-Israel memorandum of understanding, which provides exact figures for U.S. military support to Israel for a 10-year period. Unlike Ukraine’s agreements with many other partners, the U.S.-Ukraine agreement does not even include figures for the rest of this year. Although it might be challenging (though not impossible) to quantify the exact amounts of aid for Ukraine in the midst of the unpredictable war, concrete figures in the agreement (like in the U.S.-Israel memorandum of understanding) would significantly increase the credibility and predictability of U.S. support to Ukraine. The agreement provides a policy framework for potential cooperation between the U.S. president and Congress to move toward and have specific figures for the Ukrainian military aid over time. 

Mechanism for Responding to Future Attacks

Another important element running throughout all the security agreements between Ukraine and Western partners is a security mechanism to consult and deploy a collaborative response to future Russian armed attacks, including those that might take place after the end of the ongoing war.

Although the U.S.-Ukraine agreement covers any armed attacks against Ukraine (not only by Russia) and threats of armed attacks unlike agreements with other partners, it generally features much softer language than the other agreements in the section that covers the U.S. response to future Russian aggression. Namely, the U.S.-Ukraine agreement provides that in case of “future armed attack or threat of armed attack against Ukraine, the Parties shall, at the request of either Party and in accordance with their respective laws, immediately meet, where possible within 24 hours, at the most senior levels to determine appropriate next steps and additional defense needs” (emphasis added; based on the wording, this is a legally binding provision). In turn, for example, the U.K.-Ukraine agreement concretely provides that the purpose of the consultations is to “determine measures needed to counter or deter the aggression” (emphasis added), not merely “next steps” and “additional needs.”

The U.S. agreement only broadly provides that the parties may agree on a concrete response in “economic, military and/or political realms,” which may include economic sanctions. The nonbinding annex also details this provision by providing that the U.S. “intends to coordinate on the potential need to rapidly increase the scope or scale of United States security assistance to Ukraine, including potentially the provision of additional weapon systems and equipment, and other materiel” (emphasis added). As Goldsmith rightly pointed out, this wording is soft. For example, the U.K.-Ukraine agreement provides the following concrete commitment on the same issue:

The UK undertakes that, in those circumstances, and acting in accordance with its legal and constitutional requirements, it would: provide Ukraine with swift and sustained security assistance, modern military equipment across all domains as necessary, and economic assistance; impose economic and other costs on Russia; and consult with Ukraine on its needs as it exercises its right to self-defence enshrined in Article 51 of the UN Charter. [Emphasis added.]

The U.S.-Ukraine agreement’s wording increases risks that the U.S. might not contribute enough to repel potential Russian attacks after the end of the current hostilities, and thus has a negative effect on the mechanism’s ability to deter future attacks, considering the crucial importance of U.S. support. To avoid this possibility, the U.S. and Ukraine should consider significantly strengthening the wording of their agreement in this part to be at least similar to that of the U.K.-Ukraine agreement.

Termination Clause

The U.S.-Ukraine agreement is in force for 10 years. However, like most agreements with other partners, it allows both parties to terminate it with 6 months’ notice. Goldsmith called this provision “the most puzzling provision in the entire agreement,” considering how easy it is to exit it without cause. Indeed, for example, a requirement that the agreement’s termination may take place only after a certain period of its operation (like the 5-year limit in the U.S.-Bahrain security agreement) would be an important legal barrier for any future policy changes. 

The termination provision in place now, as well as its other soft features mentioned earlier, might be explained by the United States’s desire to maintain flexibility in its commitments to Ukraine. Such a short-notice termination clause leaves open room for potential negotiations with Russia (whether purposefully or not) and provides greater leverage for the U.S. to influence Ukraine’s future policy choices that depend on sustained military aid.

Ukraine has no choice but to rely on the United States’s political promises for support as outlined in the agreement. If the U.S. were to walk back on any of these promises—even within the agreement’s 6-month termination period—it could lead to potentially significant political and credibility costs in the international arena. As a side note, the agreement’s nonbinding annex that outlines the United States’s political commitments is not subject to the 6-month termination clause. According to Article XI, the termination of the agreement does not terminate implementing agreements (which includes the annex), which “shall continue to remain in effect under its own terms.” 

Interbranch Cooperation

An important drawback of the current U.S.-Ukraine agreement is the absence of congressional buy-in to the U.S. commitments in any form or shape. As I described in a Lawfare piece last year, the fact that implementation of the security agreements hinges on the relevant appropriation of the partners’ parliaments means that cooperation between the legislative and executive branches of each country is crucial to their success. Congressional approval of the U.S. commitments at least by codifying the standard of support, much like Congress did for Israel’s qualitative military edge, would significantly increase the agreement’s credibility.

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The United States and other Western partners likely have conflicting incentives for their security agreements with Ukraine. On the one hand, partners want to provide confidence to Ukraine about the stability of their support and send a message to Russia that they will back Ukraine with the support necessary for its defense. On the other hand, they may be wary that credible commitments to Ukraine may create risks of emboldening it to act aggressively, sometimes not in the partners’ interests, including not considering even reasonable ceasefire or peace options (the so-called patron’s dilemma). This dilemma combined with the absence of respective cooperation between the president and Congress (not the lack of U.S. resolve to help Ukraine) likely contributed to the relatively flexible wording of the U.S.-Ukraine security agreement.

That said, in its current flexible form, and considering the real risks of policy changes on support for Ukraine, I agree with Goldsmith that the Ukraine-U.S. agreement is not sending a particularly strong message to Russia at this moment. But, with further improvement, elaboration, and implementation, the agreement has the potential to contribute to a successful and durable U.S.-Ukraine security cooperation capable of deterring Russia.