War aims are shifting on both sides of Russia’s barbaric war against Ukraine, reflecting shifting realities on the battlefield. Unless one side can dominate the ongoing battle for the Donbas, those shifts portend a protracted war. With little prospect of a negotiated final settlement, the endgame may be a prolonged ceasefire or armistice rather than a durable end to the war. This might include a new military line of contact wherever the fighting stops, with final territorial settlements postponed until later. However this war ends, new forms of Western support will be needed to prevent peace from unraveling and to ensure that Ukraine retains the military capacity to defend itself if Russia goes back on the offensive.

Ukrainian success on the battlefield has enabled it to avoid defeat and focus energy on regaining lost sovereign territory. President Volodymyr Zelenskyy has defined victory as driving Russian troops back to their positions before the start of the war on Feb. 24, including the Line of Contact established by the unimplemented Minsk agreements. Refusing to legitimize Russian territorial conquests is a goal that the West should support, recognizing that it will require further major Russian battlefield defeats.

American goals have also evolved in step with Ukraine’s remarkable battlefield successes. While U.S. officials assert that bringing down the Putin regime is not the objective, they seek to weaken Russia’s military capability so that Putin is less able to attack Ukraine or others again. The administration has been less clear in defining what would constitute Ukrainian victory, but Washington is rightly unwilling to dictate possible peace terms to Zelenskyy.

The flow of American weapons and training has increased consistent with these evolved American goals to include combat helicopters, armored vehicles, towed artillery, counter-battery radar, advanced drones, anti-ship missiles and air defense systems. Some $4 billion worth of U.S. weapons have been transferred to Ukraine thus far with another $11 billion authorized in the emerging Ukraine Lend-Lease legislation. The U.S. is moving beyond the provision of Soviet legacy systems to include more advanced U.S. and allied technologies, supported by the necessary training and battlefield intelligence. That assistance is making a vital difference on the battlefield and could help further reverse Russian gains.

America’s allies have more diverse goals. Some favor sustaining the flow of arms needed to achieve a clear Ukrainian victory, while others want an early ceasefire to end the killing and encourage a negotiated settlement, even if it leaves more occupied territory in Russian hands. But thus far they remain fairly united, willing to supply weapons similar to those provided by the U.S. and moving, albeit slowly, toward full sanctions on Russian oil and gas purchases.

Russian losses on the battlefield have forced it to reduce its immediate war aims correspondingly from an original decapitation strategy designed to topple the Zelenskyy government. Having failed to take Kyiv, Moscow’s short-term goal now appears to be controlling Luhansk, Donetsk, the land bridge to Crimea along the Sea of Azov coast, and annexing the Kherson region to the west of Crimea. That is much more territory than Russia occupied before February 24. And Russia’s long-term ambition to subjugate all of Ukraine has probably not changed.

During his Victory Day speech on May 9, President Vladimir Putin stated falsely that his troops are now fighting Nazis on historic Russian lands, but he did not declare war or call for a nation-wide mobilization as some had expected. He appeared more defensive than usual. He knows his military campaign is making only incremental gains and could soon grind to a halt. But if he is true to his rhetoric, Putin will fight hard to avoid further retreat. That might include threats to use of unconventional weapons in Ukraine.

Shifting war aims and the prospect of protracted war could lead to a potential dilemma for Ukraine. If Russian troops can hold off the Ukrainian counter-offensive and declare a ceasefire in place, Putin could still unfortunately claim some degree of victory hoping that war-weary U.S. allies will pressure Washington and Kyiv to accede. Calling for a ceasefire to halt the killing, as several Western leaders have done, is different from agreeing to what amounts to a permanent armistice and a new frozen conflict.

Should Putin seek to freeze the conflict permanently in this way, Kyiv would need to decide how to respond. The decision would be primarily theirs. Kyiv may view a prolonged ceasefire as a defeat and continue the fight. But Russian forces, though depleted, may remain too strong and the potential costs for an exhausted Ukraine too high. So a prolonged ceasefire with a new line of contact that defers a final decision on the fate of the remaining occupied territory might be all Ukraine can achieve.

NATO nations will need to support Kyiv whichever decision it makes. It is their country and they are doing the fighting. Given diverse views in Europe, strong American leadership will be needed to maintain cohesion in the alliance.

However this war ends, the West will need to provide Ukraine with a package of at least five postwar security, diplomatic, and financial measures designed to reconstruct Ukraine and prevent Russia from again breaching a deal and renewing its attacks.

First, Ukraine’s future security will need to be guaranteed more successfully than in the past. NATO membership will be difficult to achieve immediately given opposition from several members, but after Russia’s serial violations of Ukrainian sovereignty, NATO’s door should remain open. Under the right circumstances Ukrainian membership could strengthen the alliance’s military posture and bolster stability in Central and Eastern Europe. If Ukraine is admitted to the European Union, it would gain additional guarantees from the collective defense provisions of the EU Lisbon Treaty. Individual nations also might provide various levels of bilateral security assurances, and the United States will need to decide how firm a commitment it wishes to make.

At a minimum, a continued, high level of weapons transfers, training and intelligence sharing will be needed to fortify the Ukrainian military and deter further Russian aggression over the long term.

Second, a massive new postwar Marshall Plan will be needed to reconstruct Ukraine’s destroyed infrastructure, using as much as possible confiscated Russian assets as reparations. The bill to repair Ukraine’s destroyed infrastructure is estimated at about $100 billion, with another $500 billion in related economic damage. And Europe will need to ease the return of the six million refugees that fled to other countries in the fighting, as well as another six million who are internally displaced.

Next, Ukraine’s long-term economic prosperity will need to be secured. Its GDP has collapsed by 35% or more. Massive short-term economic assistance will also be needed to keep Ukraine’s economy afloat. Whatever barriers there were to European Union membership should quickly be lifted in deference to Kyiv’s heroic stand in defense of European values. And the naval imbalance in the Black Sea must be redressed to ensure that Kyiv has guaranteed access to the sea through its remaining ports and that NATO is able to maintain a persistent deterrent presence.

Fourth, the West must unite in a diplomatic effort to deny recognition of any Russian occupied territory, including the imminent annexation of the Kherson region. Another United Nations General Assembly resolution will be needed rejecting Russian claims to occupied territory and condemning all attempts at annexing Ukrainian lands. All sanctions, especially on oil and gas, need to remain in place until Moscow returns at a minimum all territory taken since Feb. 24 so that Putin and other revisionist powers see that violating international law does not pay.

And finally, Russian war crimes must be prosecuted vigorously. The United States has asked the International Criminal Court to prosecute Russian leaders and Washington supports a separate United Nations efforts to investigate. All America’s allies should join this chorus.

Having underestimated the Ukrainians’ determination to defend their freedom, the United States and its allies should work for a Ukrainian victory as long as Kyiv remains ready to continue the fight. When the war ends, these five measures will provide Ukraine with the ability to thrive in a post-war environment.

Hans Binnendijk is a Distinguished Fellow at the Atlantic Council; he served previously as NSC Special Assistant to the President for Defense Policy; as Acting Director of State’s Policy Planning Staff, and as Director of the Institute for National Strategic Studies.

Alexander Vershbow is a Distinguished Fellow at the Atlantic Council; a career US diplomat, he served as NATO Deputy Secretary General, Assistant Secretary of Defense for International Security Affairs, and Ambassador to NATO, Russia, and the Republic of Korea

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