The outcome of next month’s U.S. presidential election will be pivotal in shaping not only the course of the war in Ukraine, but the future of democracy around the globe. Following Russia’s failed initial strategy to capture Kyiv in February of 2022, and with things largely bogged down in attritional warfare since then, Ukraine has effectively defended most of its territory. What happens next will hinge on the landscape of support from the U.S. and how Ukraine navigates an increasingly challenging military and diplomatic situation.

If Vice President Harris wins, it’s expected that U.S. support for Ukraine will continue and potentially even expand, reflecting an ongoing commitment to counter Russian aggression and support European allies in maintaining security on the continent. Under a Harris administration, the U.S. and NATO could back Ukraine’s efforts to mount a new offensive, bolstered by significant investments in defense and a growing military-industrial base among NATO members. Under this scenario, Ukraine could realize significant military gains within months, cementing Ukraine’s position in a Western alliance that has the resolve—in deeds, not just words—to defend democracy and thwart the spread of Russia’s anti-liberal, anti-truth, anti-rights agenda.

Conversely, a Trump victory appears almost certain to produce a dramatic shift in U.S. foreign policy. Isolationism would become the guiding principle of an aggressive “America First” strategy. Cessation of support for Ukraine would take center stage. A Trump administration, if we take Candidate Trump at his word, would pursue friendly relations with Russian President Vladimir Putin and disengage from European security matters. Trump appears to value a halt to hostilities over all else, claiming that he could achieve this “in one day,” even if that means ceding to Putin the Ukrainian territory Russia currently occupies. This abandonment would severely limit Ukraine’s capacity to defend itself and would likely embolden Russian advances in other areas, undermining NATO’s collective defense. Populist authoritarians around the world would respond with glee. This course of events would bolster their capacity to act with impunity against any and all opposition.

There are things Ukraine can do now to prepare, either way. Ukrainian President Volodymyr Zelensky can clarify his country’s near-term military strategy and theory of victory. Exactly how would he deploy enhanced support and authority to use the full capabilities of weapons systems supplied by any U.S. administration? What is Ukraine’s plan for increasing domestic arms production? How will Ukraine mobilize additional troops and get them ready for a new combined-arms offensive? What role will Ukraine’s ongoing innovations in drone warfare play? How can collaboration with the U.S. and NATO on training and operational planning best assist?

In sum, the next phase of Ukraine’s military efforts hinges not only on its own strategies and preparations but also on the choices American voters make in November. Those choices will have profound consequences not only for Ukraine, but for the freedoms of people across Europe and around the world.