New Insights from the RAND National Security Research Division

May 14, 2024

by Samuel Charap and Miranda Priebe

There is no end in sight for the Russia-Ukraine war, and it is a nearly impossible task to predict when the fighting will stop or what the international situation will be when it does. But no matter when—or how—the conflict ends, Russia will remain a threat both to Ukraine and to the interests of the United States and its allies. The way that the United States approaches its relationship with Russia after the war will affect U.S. interests in Europe and, likely, around the globe. Given these stakes, U.S. strategists need to start planning for the postwar period now. A new RAND study and accompanying research brief use an alternative futures analysis to help policymakers consider the options they have for dealing with Russia after the war.

Past wars involving major powers have taught us lessons about the importance of the decisions that are made in the aftermath of conflict. The settlements following the First and Second World Wars reshaped nations, societies, and the international order in ways that are still felt today. While the United States cannot determine the outcome of the war in Ukraine, U.S. wartime policies can have an impact on the trajectory of the conflict—and will likely have ripple effects long after the fighting ends. Planning for the war's aftermath now can help ensure that current policies promote the postwar conditions that best serve long-term U.S. interests.

When many outcomes are possible, it can be helpful to assess how different strategic choices might play out in different postwar contexts. For example, if the U.S. adopts a hardline approach—e.g., punishing Russia through sanctions while also enhancing U.S. force posture in Europe—in a postwar world that is less favorable to U.S. interests—e.g., in which the current conflict ends with a weak ceasefire after a long war of attrition, China provides Russia with lethal aid, and Ukraine suffers modest territorial setbacks—the postwar decade could be characterized by pervasive instability on the ground in Ukraine, between Russia and NATO in Europe, and at the strategic level between the United States and its two main nuclear rivals, Russia and China.

Alternatively, if the U.S. adopts a less hardline approach—e.g., being open to negotiations and more-restrained political and military policies aimed at stabilizing relations with Russia—in a world that is more favorable to U.S. interests—e.g., in which the conflict ends soon with a robust ceasefire, China doesn't provide Russia with lethal aid, and Ukraine makes modest territorial gains—the postwar decade could be characterized by a 'cold peace,' or greater strategic, regional, and local stability.

Some have argued that any softening of the U.S. stance could invite further Russian aggression, possibly against a NATO member. Following this logic, even after the war is over, Washington needs to sustain a hardline approach to punish and deter Moscow and send a message of resolve to other rivals. Russia would be emboldened, according to this view, by any moderation of U.S. policy, such as returning force numbers in Europe to prewar levels.

But Moscow's decision not to attack NATO member-states—even as these states continue to provide aid to Ukraine during the war—demonstrates the strength of the alliance's deterrent. The erosion of Russian power during the war makes it even less likely that the Kremlin would engage in opportunistic aggression against a U.S. treaty ally. Furthermore, past RAND research has found that moderately less hardline policies have not provoked weaker rivals to become more demanding and aggressive. While NATO should always be prepared for potential contingencies, the United States and its allies have options for how to manage the threat that Russia poses in the future. Hardline U.S. postwar policies also could make conflict with Russia more, not less, likely. For example, such policies could increase the risk of a war brought about by Kremlin misperception of U.S. intentions.

The way the war ends will likely have long-term consequences. For example, a robust ceasefire agreement that has measures such as demilitarized zones and dispute resolution mechanisms would lower the risk of conflict recurrence. Therefore, the United States could begin preparatory work today to make such an outcome more likely (as we detail in an earlier report). Many of the key elements of a ceasefire can be thought through before the guns fall silent to increase the chances that the United States, its allies, and Ukraine will be ready when the time comes.

Additionally, current U.S. security assistance to Ukraine can begin to take into account the core postwar priority of preventing a renewed Russian attack. Specifically, the United States can focus its assistance on enabling a so-called "porcupine strategy" that optimizes Ukrainian forces for defending the territory it holds at the end of the war (rather than for going on the offensive). A porcupine strategy would aim to deter Russia from attacking again by increasing Ukraine's ability to raise the costs and reduce the likelihood of success of another invasion.

This summary is derived from Planning for the Aftermath: Assessing Options for U.S. Strategy Toward Russia After the Ukraine War, by Samuel Charap and Miranda Priebe.

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