Ukrainians will continue to fight Russian forces that have been invading, occupying and bombing their country not just since Russian President Vladimir Putin launched his full-scale invasion in February 2022 but since the illegal annexation of Crimea in 2014 and the initial invasion of Ukraine’s Donbas region. This is true whether or not Congress passes President Biden’s supplemental request, which includes $61 billion in assistance for Ukraine. Passage of the assistance, however, could mean the difference between Ukrainian victory and defeat.   

Defeat would put Ukraine at the mercy of a Kremlin determined to stamp out a separate Ukrainian identity and expose other countries in the region to potential Russian advances. It also would deal a serious blow to U.S. leadership and prestige and require more costly measures than current aid to Ukraine to defend vital American interests in Europe. 

Ukrainians have shown tremendous courage and determination in defending their land, their freedom and their lives from Putin’s brutal assault that has included war crimes, crimes against humanity and even genocide. Despite being outnumbered and outgunned, and in defiance of predictions of many, including Putin, that they would be quickly defeated, Ukrainians have regained control of more than 50 percent of the land Russian forces initially occupied.  

Since last summer, when the much-touted Ukrainian counter-offensive began, Ukraine has successfully driven Russia’s Black Sea Fleet out of its base at Sevastopol. The counter-offensive has fallen short of the hopes many, including the three of us, had; but those hopes were never realistic given the time Russia had to prepare its defenses and the foot-dragging by the West in delivering Ukraine what it needed to breach those defenses.    

Congressional approval of assistance to Ukraine would not lead to an immediate military victory for Ukraine, as it will take time to get long-promised weapons into Ukrainian hands. But it would be an enormous morale boost for Ukrainians who are doing the fighting and for Ukraine’s leadership, and, at a minimum, it would prevent a Russian victory.   

On the flip side, Putin anticipates Congress will fail to pass the supplemental. Proving him wrong would be a blow to his designs on Ukraine and also to Russian forces on the frontline, who have suffered more than 300,000 killed and wounded. They will see no end in sight in their being treated like cannon fodder and might, at some point, with their morale sagging, say enough is enough. 

The Europeans, who have surpassed the United States in assistance pledged and provided to Ukraine, will be inspired to continue that help with congressional passage of the supplemental. Meanwhile, accommodationists in the West who are ready to sacrifice Ukrainian territory and millions of Ukrainians to endless Russian occupation will see their dangerous efforts spoiled.  

Ukrainians have never asked that we send our troops to fight their fight for them, but they do need our weapons and assistance. Despite the terrible loss the country has endured, Ukrainians by huge margins reject territorial concessions to Putin and negotiations with a Russian leader who has repeatedly shown that his word on agreements means nothing. Ukrainians remain optimistic about their country’s chances of winning the war, according to a recent survey.  

Ukrainians’ steely determination to see this war to victory — defined as driving every Russian soldier from Ukrainian land and regaining control over the remaining 20 percent or so of occupied territory — is remarkable when one thinks of the terrible loss their country has suffered and questions they have about the West’s commitment to continue to support them.  

Accommodationists in the West ignore Russian war crimes in occupied Ukraine and what would happen to more Ukrainians if Moscow were to control other parts of the country; nor do they recognize the danger in rewarding Putin’s aggression. Moreover, Putin has indicated no interest in any negotiated end to the war, despite naïve reporting and commentary to the contrary.  

“If Ukraine doesn’t have support from the EU and the US, then Putin will win,” Irish Prime Minister Leo Varadkar said last month at the European Union summit. And Ukraine will lose. It’s that simple.  

If the West stops aid to Ukraine, other European nations such as Moldova and Georgia may be Putin’s next targets. Putin may even feel emboldened to test NATO member states such as the Baltics or new member Finland. For hundreds of years, as Central and East European nations know too well, Russia has threatened, oppressed and invaded its neighbors. Under Putin, that tendency obviously hasn’t stopped. 

Moreover, China will become more assertive, increasing the odds of an attack on Taiwan and creating an opening for a more muscular Chinese policy in the South China Sea.  Iran, too, which has provided vital support to Moscow in its campaign against Ukraine, will feel emboldened and will likely think it can get away with creating more mayhem in the Middle East, endangering our forces in the region and those of our allies. U.S. leadership will be undermined.   

If U.S. assistance stops, the Russians will be able to push farther into Ukraine, threatening a coherent Ukrainian defense, even putting Kyiv at risk. Should that happen, the Ukrainians would continue to fight, but the war would degenerate into a bloody and protracted insurgency. 

We already see what happens when Western assistance slows — Ukrainian forces have already had to cut way back on their defensive artillery fire. For example, Europe has fallen woefully short in delivering a promise of a million artillery shells to Ukraine. The United States has dragged its feet on delivery of a number of vital weapons systems, including more air defense systems. This has enabled Russian forces to move back closer to the line of contact, mounting many attacks up and down that line, as well as brutal missile campaigns against all parts of Ukraine.   

Congress and the administration can avoid all of this by finding compromise over border policy. This will free up assistance to Ukraine since the issues were tied together in the Biden administration’s supplemental request. There remains strong support in the Senate and enough support in the House for helping Ukraine, but even strong proponents of Ukraine want to see a deal on the border to secure their votes.  

With sufficient long-range fires, adequate air defense, a full drone army, squadrons of F-16 fighters — all of which is possible with promised American and European funding — the Ukrainian military can turn the tide and push Russian forces back toward Ukraine’s internationally recognized borders of 1991.  

Victory for Ukraine is possible, but Western assistance is critical for it to happen. More delay will prove incredibly costly, underscoring the urgency to help Ukraine turn the tide and deal Putin a fatal blow.

David J. Krameris the executive director of the George W. Bush Institute and a former assistant secretary of state for the Bureau of Democracy, Human Rights, and Labor in the George W. Bush administration. John Herbstis the senior director of the Atlantic Council’s Eurasia Center and a former U.S. ambassador to Ukraine. William Tayloris a former U.S. ambassador to Ukraine.