Securing Ukraine: Next Steps

Charles A. Kupchan is a senior fellow at the Council on Foreign Relations and professor of international affairs at Georgetown University.

This Ukraine Policy Brief is part of the Council Special Initiative on Securing Ukraine's Future and the Wachenheim Program on Peace and Security.

Executive Summary

President Donald Trump is right to launch a diplomatic effort to end the war in Ukraine. Ukraine has virtually no prospect of defeating Russian forces and restoring its territorial integrity. Yet Trump has made no progress, and Russian forces continue to conquer additional Ukrainian territory. If Trump is to deliver on his promise to end the war in Ukraine, he will need to offer the Kremlin inducements: the prospect of improved relations with the United States and reassurance that Ukraine will not join NATO if and when Russia ceases its aggression. But Trump will also need to impose greater costs on Russia for continuing its war of aggression. The United States and its European allies will have to tighten economic sanctions and ensure that they continue to provide Ukraine the weapons it needs to defend itself.

Introduction

President Donald Trump is right to launch a diplomatic effort to end the war in Ukraine. Even with sustained support from the United States and Europe, Ukraine has little prospect of generating the manpower and military capability to defeat Russian forces and restore its territorial integrity. Indeed, Russia has been making steady, if small and costly, gains on the battlefield since late last year. And time is not on Ukraine’s side. President Trump has already made clear his frustration with Ukraine’s ongoing need for U.S. weapons, shouting down Ukrainian President Volodymyr Zelenskyy in an Oval Office meeting in February. In the United Kingdom and most EU member states (Hungary and Slovakia are exceptions), support for robust military and economic aid to Ukraine remains steady. But that could change if far-right parties such as Alternative for Germany (AfD) in Germany, the National Rally in France, and Reform UK keep gaining political strength. A war that drags on for years could well mean that Ukraine loses substantially more territory to Russia and risks becoming a failed state.

Yet even if Trump is right to try to end the war diplomatically, he has made no progress toward doing so. Russia is launching a new summer offensive, hitting Ukraine with the war’s largest waves of drone and ballistic missile strikes, and showing no sign that it is negotiating in good faith. On the contrary, the Kremlin appears to be merely going through the motions of diplomatic engagement while continuing to pursue its maximalist war aims: the demilitarization, neutralization, and so-called denazification of Ukraine. Russian President Vladimir Putin is still determined to subjugate the country.

If Trump has any chance of delivering on his promise to end the war in Ukraine, he will need to impose greater costs on Russia for continuing its war of aggression. Trump has offered Putin the right carrots—holding out the prospect of a repair of political and economic relations between the United States and Russia and taking NATO membership for Ukraine off the table. But Washington now needs to pair those inducements with more coercion by tightening economic sanctions against Russia and making it clear that the United States will continue to provide Ukraine the military assistance it needs to defend itself. By spurning Trump’s initial diplomatic overtures and continuing to expend many Russian lives and resources for only incremental battlefield gains, Putin has demonstrated that he will stop attacking Ukraine only if he deems his maximalist war aims to be unattainable. Ukraine therefore needs to amass the military wherewithal to blunt further Russia advances and drive home to the Kremlin that its goal of subjugating Ukraine is out of reach.

The proposal to end the war that the Trump administration has put on the table has considerable potential. A ceasefire would take effect along the current front line, leaving Russia in control of the roughly 20 percent of Ukrainian territory that it now occupies. But the 80 percent of Ukraine that is still free must emerge as a secure and sovereign state if that deal is to be acceptable. Arriving at that outcome will require NATO members to give Kyiv the weapons it needs to ensure that Russia cannot conquer any more Ukrainian territory. Ukraine would not give up on restoring its territorial integrity, but it would defer that goal to negotiations down the road.

The Carrots: Rehabilitating U.S.-Russia Relations and Closing the Door to Ukraine’s NATO Membership

Trump’s effort to end the war is a welcome contrast from his predecessor’s approach. U.S. President Joe Biden had a policy of supporting Ukraine for “as long as it takes.” But that open-ended objective left the administration without a credible strategy that matched realistic ends to available means. Trump has downsized U.S. objectives and is aiming for an appropriate and attainable end: a ceasefire in place. He now needs to upsize the means if he is to secure that outcome. Trump must change Putin’s cost-benefit analysis by making Russia’s ongoing aggression increasingly costly, while offering the Russian president appealing benefits if he agrees to end the war.

The prospect of building a good relationship with Trump and ending Russia’s economic and diplomatic isolation is perhaps the most appealing carrot that Trump can present Putin. Putin craves recognition as the leader of a great power, and summit meetings and trade deals with the U.S. president can check that box. Russia and the West will probably not enjoy meaningfully normal relations until the post-Putin era, but Trump can provide Putin at least some measure of rehabilitation. That rehabilitation would in turn give Putin a “Western” option, which may be increasingly attractive as a way of hedging against Russia’s mounting economic and strategic dependence on China. Indeed, as a document disclosed by the New York Times reveals, Moscow’s intelligence services view Beijing with deep suspicion and believe that it poses a serious threat to Russian security.

Trump can also offer Putin an effective end to Ukraine’s bid for NATO membership. Though the Trump administration’s opposition to Ukraine’s entry into the alliance is controversial, it is the right move. Russia has very legitimate reasons to object to Ukraine’s integration into NATO; granting Kyiv membership would put enormous military potential on the other side of Russia’s one-thousand-plus-mile border with Ukraine. Accordingly, Putin is much more likely to agree to a ceasefire if he is confident that NATO will not thereafter admit Ukraine to its ranks.

Russia is hardly alone in wanting to keep potent military threats away from its borders. Great powers, regardless of their ideological bent, do not like it when other great powers—not to mention the world’s strongest military alliance—stray into their neighborhoods. General Keith Kellogg, Trump’s special envoy for Ukraine and Russia, was right to recently call Russia’s objections to Ukraine’s entry into NATO “a fair concern” and to affirm that “Ukraine coming into NATO is not on the table.” For Trump to formalize this position would help reassure Putin that he has successfully addressed at least some of what he calls the “root causes” of the war, helping convince him to agree to a durable ceasefire.

To be sure, taking NATO membership off the table would dash the hopes of a country still suffering Russian aggression and understandably keen to join the alliance. But Washington should shoot straight with Kyiv; a consensus within NATO to invite Ukraine will be unattainable for the foreseeable future. Confronting that reality would both help convince Putin to back off and allow Kyiv to pursue more realistic options for ensuring Ukraine’s security.

Yet just as there is no consensus within the alliance to invite Ukraine to join, there is also no consensus to formally close the door. This lack of agreement explains why the declaration released at NATO’s June summit in The Hague was silent on the issue. Accordingly, it will be up to Washington and its like-minded partners, not NATO as a collective body, to make it clear that Ukraine is not on a path to membership. In the meantime, NATO should continue to reiterate its usual position that its doors remain open. This stance communicates to Russia that it has no veto over the enlargement of the alliance. It keeps the alliance open to aspirants in the Balkans. And perhaps Ukraine will one day join as well—but only well down the road in a very different geopolitical landscape.

The Sticks: Sanctions Against Russia and Arms for Ukraine

Putin’s diplomatic intransigence has made amply clear that carrots alone will not produce a ceasefire on terms acceptable to Ukraine. As negotiations with Russia continue, Trump has at his disposal two main instruments for increasing his coercive leverage over Moscow: tightening economic sanctions and reupping military assistance to Ukraine. Although additional economic sanctions can help constrain Russia’s war effort, their likely impact will be limited. Trump should therefore focus on ensuring that Ukraine has the weapons it needs to defend itself.

Increasing Sanctions Against Russia

Western governments have a range of options for tightening the economic screws on Russia. The Sanctioning Russia Act of 2025, a Senate bill with over eighty cosponsors, contains multiple provisions, including broader sanctions against Russian banks, a U.S. prohibition on imports of Russian uranium, and tariffs of at least 500 percent on all imports from Russia. Its most draconian provision calls for tariffs of at least 500 percent on any country that imports Russian fossil fuels, including China and India.

Other options include barring all Russian financial institutions from accessing the U.S. financial system. Washington could broaden sanctions against Russia’s oil and gas companies and impose secondary sanctions against banks in China, India, and other countries that do business with sanctioned Russian companies. Edward Fishman, a leading sanctions expert, suggests that importers of Russian energy should sequester in their own banks the revenues they owe Russia and release such funds only for limited, nonmilitary uses. Stephen Sestanovich, a Russia expert and CFR fellow, recommends reducing the $60-per-barrel price cap on Russian oil, which would further constrain Moscow’s ability to fund the war. Energy exports are a major source of revenue for the Russian government, which devotes some 40 percent of its budget to military and security spending. In 2022, the G-7 agreed to impose a $60 cap on the price of Russian oil, so bringing down that cap would further reduce these revenues and put additional constraints on the war effort. Finally, the United States and Europe could also seize the roughly $300 billion they hold in frozen Russian assets and use those funds to support Ukraine.

Increasing sanctions along these lines would certainly raise the economic costs of Russia’s continuing aggression against Ukraine. Tightened restrictions would also signal to Putin that the United States and its allies remain steady and united in their determination to defeat Russia’s effort to subjugate Ukraine. Yet the potential impact of increased sanctions should not be overstated.

Of the three main lines of the West’s effort to respond to Russia’s full-scale invasion—arming Ukraine, bolstering NATO’s eastern flank, and imposing economic sanctions on Russia—sanctions have been the weakest link. Following the initial imposition of far-reaching restrictions in 2022, the Russians exploited various loopholes to amass hard currency. They quickly found new buyers for their energy exports, as well as trading partners that could help Russia procure items needed for its military and military-industrial complex. The dampening impact of sanctions on the Russian economy was also offset by the high levels of domestic spending that accompanied the nation’s war footing.

To be sure, the extensive options described above that aim to deny Russia income from its energy exports could cripple the Russian economy and its war effort. But these options simply are not realistic. Imposing a 500 percent tariff on China for buying Russian energy would likely lead to the breakup of the global economy. It is equally hard to imagine that banks in China and India would willingly sequester revenue from the sale of Russian fossil fuels. China has already made it clear that it is willing to be Russia’s economic lifeline and India is committed to a “multi-alignment” strategy that precludes punishing Russia. Trump has already indicated that he is ambivalent about increasing sanctions against Russia. If he does agree to do so, Washington’s next moves are quite likely to be incremental in nature, not the nuclear options that have the potential to be game changers.

It is also the case that sanctions take time to impose real economic hardship. As Fishman notes, “sanctions are a marathon, not a sprint. . . .The safest assumption is that Moscow can continue funding the war effort for at least a few more years, if Putin so chooses.” But a few more years is too long a time in a war that has already caused untold destruction and killed or wounded some 1.5 million Russians and Ukrainians.

This war needs to end as soon as possible. Increasing sanctions can help attain that objective. But it is the readiness of the United States and Europe to give Ukraine the arms it needs to defend itself that offers the best hope of attaining a ceasefire in the near future.

Arming Ukraine

Putin has spurned U.S. efforts to secure a ceasefire, clearly preferring to keep the war going. As the Kremlin has openly stated, it seeks to occupy more Ukrainian territory, at a minimum gaining control of the entirety of the four regions that Russia has formally annexed. Moscow continues to talk about addressing the “root causes” of the war in Ukraine, which means removing what it erroneously calls the “neo-Nazi regime” in Kyiv, demilitarizing Ukraine and ensuring its geopolitical neutrality, and rolling back NATO forces from the alliance’s eastern flank.

These conditions are all nonstarters. Neither Ukraine nor its European supporters will accept a ceasefire that does not ensure that free Ukraine is sovereign and secure. Especially after Russia’s invasion of Ukraine, the ongoing threat Russia poses to European security, and the recent entry of Finland and Sweden into NATO, rolling back the alliance’s presence on its eastern flank is out of the question. On the contrary, NATO members are increasing defense spending, deploying additional forces to frontline countries, and preparing contingency plans for defending every inch of alliance territory.

Given the expansive scope of Russia’s war aims, Putin will limit those aims only when he has no choice but to do so. Getting a ceasefire on terms acceptable to Ukraine and its supporters therefore entails a commitment from NATO members, especially the United States, to provide Ukraine the military wherewithal to defend itself today and for the indefinite future.

The Trump administration has not yet indicated whether it intends to ask Congress for more funding to support Ukraine once the appropriations left over from the Biden administration run out. Yet Trump should commit to doing so in the near future, sending a message to the Kremlin that Washington intends to line up with European allies to make sure that Ukraine has the weapons it needs.

A number of factors should, and probably will, push Trump to make that commitment. Trump has been become increasingly frustrated with Putin over both his unwillingness to negotiate in good faith and his continued pummeling of Ukraine. Trump may well come around to the reality that he needs to confront Putin with sticks, not just carrots.

The costs of supporting Ukraine are also decreasing. Much of the fighting is now taking place using unmanned drones, which Ukraine can produce domestically. The focus on drone warfare, along with more static front lines, means that the Ukrainian military is no longer burning through the artillery, armored vehicles, and other weapons provided by the United States and its allies. Indeed, Ukraine is now producing domestically some 40 percent of the weapons it needs on the front line, a share that will increase as the country’s military-industrial base continues to grow.

The minerals deal that the United States and Ukraine signed in late April, by creating an investment fund through which Washington will be compensated for future military aid, will also help Trump build political support for continued assistance to Kyiv. As he campaigned for office, Trump expressed skepticism toward aid to Ukraine, while his running mate, Senator J.D. Vance (R-OH), explicitly opposed the $61 billion package that Congress eventually approved in April 2024. One plank of Trump’s America First foreign policy is that the U.S. government should spend more taxpayer money addressing problems at home and less on problems in distant lands—one of the reasons that Trump dismantled the U.S. Agency for International Development. The minerals deal circumvents this political obstacle to aiding Ukraine by counting future U.S. military assistance as a capital contribution to the minerals investment fund.

Compared with economic sanctions, which take time to have an impact, military assistance produces results quickly. Now that Ukrainian forces are fully trained in the use of sophisticated U.S. weapons, such as Patriot air defense interceptors, high mobility air rocket systems (HIMARS), and army tactile missile systems (ATACMS), such weapons can be put to good use the moment they are deployed. As the Trump administration is seeking to end the war sooner rather than later, immediately blocking further Russian advances offers the most promise of convincing Putin to back away from his maximalist war aims and settle for a ceasefire that leaves free Ukraine sovereign and secure.

The Endgame: A Stable, Secure Ukraine as an EU Member State

The urgent focus of the United States and its allies should be to build up a force in Ukraine capable of shutting down Russia’s efforts to seize more Ukrainian territory and to ensure that Ukraine has what it needs to defend itself over the long haul. Kyiv needs to not only stop the Russians but also amass the military capability required to deter and, if necessary, defeat future Russian aggression.

Looking over the horizon, Washington should also start laying the diplomatic groundwork for deploying an international peacekeeping and monitoring force along the ceasefire line. To secure the buy-in of both Russia and Ukraine, this multinational force would ideally operate under an Organization for Security Cooperation in Europe (OSCE) or UN mandate. The force should include soldiers from countries that have sought to play mediating roles, such as India, South Africa, and Turkey. This peacekeeping and monitoring force should have less restrictive rules of engagement than the OSCE monitoring mission that was established in 2014. It would oversee a pullback of forces from the front line, patrol the line of contact, and investigate violations. Drones, cameras, and other sensors would help monitor a line of contact that stretches some six hundred miles.

Once a stable ceasefire has taken hold, the European Union should oversee reconstruction. The EU should map out a rigorous accession roadmap that will help Ukraine, which is already a candidate for membership in the union, implement the painful political and economic reforms needed to join. Fighting corruption and helping Ukraine reform its economy would also build political stability and societal resilience. Ukraine’s eventual accession into the EU would also bring with it the security guarantee provided for in Article 42.7.

By the time Ukraine enters the EU, it should be a stable and secure democracy. By that time, Russia will likely have entered the post-Putin era, making it conceivable that Moscow will no longer harbor aggressive intent toward Ukraine. If so, Ukraine might then have an opportunity to restore its territorial integrity—but at the negotiating table, not on the battlefield.

Recommendations

The United States and its European allies should take several concrete steps to end the war in Ukraine.

• The Trump administration should continue efforts to broker a ceasefire in Ukraine. Neither Russia nor Ukraine has the military capability to defeat the other. This war will end at the negotiating table, not on the battlefield.
• As inducements to Putin, the Trump administration should offer the Kremlin the prospect of a gradual loosening of Russia’s economic and diplomatic isolation. Washington should also explicitly take Ukrainian NATO membership off the table, a move that would make it easier to convince Putin to end the war.
• To raise the costs of Russia’s continued aggression, the Trump administration should work with its European partners to tighten economic sanctions and ensure that Ukraine will, for the foreseeable future, receive the military and economic assistance it needs to defend itself and rebuild.
• The proposal that has emerged from Trump’s diplomatic efforts is sound: a ceasefire, with Russia holding on to the roughly 20 percent of Ukrainian territory that it currently occupies. But that deal is acceptable only if the remaining 80 percent of Ukraine emerges as a sovereign, secure, and prosperous democracy.
• To prepare for a lasting diplomatic end to the war, Washington should spearhead efforts to ready an international peacekeeping and monitoring force for deployment along the ceasefire line.
• Once a stable ceasefire has taken hold, the EU should take the lead in overseeing reconstruction and Ukraine should expedite its accession to the EU.

Conclusion

At the 2025 NATO summit in The Hague, NATO members agreed to increase defense spending to 5 percent of gross domestic product (GDP), a significant increase from the previous target of 2 percent. That decision is a judicious response to a European security order again threatened by Russia. Yet the future of transatlantic security also depends on ending Russia’s aggression against Ukraine and ensuring that free Ukraine emerges as a success story. Attaining that objective will require NATO members to provide Ukraine what it needs to defend itself, convincing Putin to agree to a ceasefire by blocking Russian forces from gaining more territory. Putin will stop only when he is stopped.

This work represents the views and opinions solely of the author. The Council on Foreign Relations is an independent, nonpartisan membership organization, think tank, and publisher, and takes no institutional positions on matters of policy.