At the NATO Summit in June, Ukraine’s President Volodymyr Zelensky called on U.S. President Joe Biden to give a clear ‘yes’ or ‘no’ answer to his country’s request for a Membership Action Plan (MAP), the formal pathway to membership of the organisation. Zelensky added that Ukraine was more ready than most EU countries were to join NATO. President Biden responded that ‘school’s out’ on whether Ukraine had made enough progress in eradicating corruption and fulfilling other criteria to enter the Alliance. Moreover, he stated that the issue depended not only on him, but also on the other allies.

It is, however, a common misunderstanding that Ukraine’s inability to join the transatlantic alliance is primarily down to its domestic reform progress. The real reason is geopolitical: namely, NATO cannot invite new members that it is unable to defend. When President Zelensky visits the White House on 30 August, President Biden needs to tell him what he cannot say publicly – that Ukraine should stop pushing for a MAP, because Russia’s military superiority in the region prevents this from happening.

Defence and Deterrence

The eastern enlargement debate goes back to the Bucharest Summit in 2008, when NATO promised that Ukraine (as well as Georgia) would become a member, without specifying when and under what circumstances this could happen. Russia’s aggression against Georgia later in 2008 and against Ukraine since 2014 has severely curtailed NATO’s ambitions for expansion. At no point during Russia’s regional reassertion has NATO shown a willingness to intervene militarily. Earlier this year, Russia stationed around 100,000 troops on the Ukrainian border in an apparent attempt to stifle renewed hopes in Kyiv about entering a MAP following the election of President Biden.

NATO’s credibility depends on its ability to defend its members against external aggression, as enshrined in the North Atlantic Treaty’s Article 5 mutual defence obligation. NATO must back up the accession of a new member on Russia’s borders with a credible and solid deterrent, otherwise Moscow will be tempted to test the Alliance’s resolve and ability to react to a crisis. Mere membership will not deter Russia, as the latter may seek to expose any expansion as a bluff and hence undermine the Alliance’s credibility. The real question regarding Ukraine’s membership aspirations, therefore, is whether NATO Allies are willing and able to invest in the immense effort required to make collective defence credible.

NATO’s increased conventional defence and deterrence in Poland and the Baltic states since 2014 serves as a relevant comparison for what it would take to defend Ukraine. The Alliance put in place rotating multinational battlegroups as an assurance ‘tripwire’ and doubled the size and reaction capacity of the NATO Response Force. Separately, as part of its multi-billion dollar European Deterrence Initiative, the U.S. has positioned equipment in Poland and conducted large-scale military exercises, which make up the backbone of the broader effort to deter Russian aggression on NATO’s eastern border. Despite this effort, wargames have concluded that Russia would probably be able to overrun the Baltic states in a matter of days, unless NATO deploys a more substantial defence capacity.

If NATO were to grant a MAP to Ukraine, it would have to start preparing for an unprecedented deterrence effort against Russia. Assuming that NATO and Ukraine could find a modus vivendi on Crimea and the part of Donbas under Russian control, the Alliance would face the unrealistic task of deploying the vast military force required to defend a country the size of Ukraine. This would most certainly have to involve permanent forces, which would contradict the NATO–Russia Founding Act of 1997 preceding the first enlargement, the spirit of which the Alliance wishes to maintain. Doubts about defending NATO’s current borders serve to undermine any rationale for extending security guarantees further eastward. Moreover, NATO troops would have to be retrained and restructured to counter the grey-zone operations that Russia relied on in Ukraine in 2014.

Missing Reforms

For the past 13 years, policymakers have continued to stress Ukraine’s lack of reforms as the reason for its inability to join the Alliance. It is true that Ukraine has not delivered the kind of transition that it set itself as a goal after 2014, and in which Western countries have invested heavily. As President Biden correctly pointed out, Ukraine’s fight against corruption has been particularly disappointing. In recent years, the EU, the U.S. and the IMF have invested in specialised legal infrastructure to fight corruption at the highest level of state power. However, the systematic undermining of this infrastructure has prevented any high-level person from even coming close to a conviction.

Ukraine’s inability to deliver positive reforms also relates directly to NATO business. On the one hand, Ukraine should be commended for having built up a fighting capability to contain Russian-instigated separatism in the Donbass since 2014. On the other hand, the country has a much less impressive record of implementing Euro-Atlantic standards in the governance of its security sector. This includes strengthening the role of the Ministry of Defence in the day-to-day management of the armed forces (and diminishing the role of the presidential administration), the adoption of a NATO-style command and control structure, and reducing the extensive powers of the Security Service in Ukraine in accordance with the norms of Western intelligence services.

Ukraine’s domestic reforms are an important part of demonstrating its desire to stand with NATO Allies. If Ukraine could show convincing progress in the fight against corruption and security sector reform, NATO would be more readily convinced that the country is part of the West, and not only in words. In the end, however, it is primarily the weakening of NATO’s deterrence capacity, and not the lack of reform, which prevents the Alliance from embracing Ukraine. NATO can never admit this though, because it would mean publicly bending to Russia’s bullying methods.

Distant Aspirations

At their meeting in the White House on 30 August, President Biden will have plenty of things to discuss with President Zelensky, including his decision to drop sanctions related to the construction of Nord Stream II. After all, Ukraine is the single most important country in the confrontation between Russia and the West, and one that NATO and the U.S. have an unmistakable interest in keeping as a close partner.

As long as the geopolitical reality remains as it is, NATO membership will continue to be a distant aspiration for Ukraine. The disastrous retreat from Afghanistan will lead NATO to focus on safeguarding the credibility of Article 5, especially in the near future. Biden should make clear that Ukraine faces immense challenges in fighting corruption and that this continues to be a vital part of the country’s aspirations to become a more accountable and prosperous state.

Biden also needs to be honest about the fact that Ukraine’s membership chances primarily depend on the regional military realities. He should privately appeal to Zelensky and his government not to continue to call for a MAP, because this puts the U.S. and NATO in an uncomfortable position and could force them to publicly state the real reason why it cannot happen. The best NATO and the US can realistically offer against external aggression is continued funding, advice and training to increase the resilience of Ukraine’s armed forces.

The views expressed in this Commentary are the author’s and do not represent those of RUSI or any other institution.