In late summer of 2022, Ukraine launched a major counteroffensive in the country’s south. On Nov. 11, that operation resulted in the liberation of the city of Kherson and all the previously Russian-occupied areas west of the Dnipro River.
Amid the euphoria of Ukraine’s return to Kherson, little attention was paid to the remarkable escape of Moscow’s trapped forces. Over the course of several weeks, an estimated 20,000 to 30,000 Russian soldiers, including elite units that had been sent to fortify the front, and massive troves of military equipment, were safely evacuated across the Dnipro using ferries, pontoons, and a bridge that the Ukrainians had previously made partially impassable. The Ukrainians had been hitting the crossing with rocket artillery ahead of the retreat, but then all but stopped firing at the vulnerable bottleneck for several weeks as the bulk of the Russian forces crossed. “Withdrawing from Kherson in good order was Russia’s most successful military operation of the entire war,” George Barros, who heads the Russia team at the Institute for the Study of War told Foreign Policy. Had this force been annihilated or forced to surrender, it would have marked a turning point in the war—and a tremendous humiliation of the Kremlin before the entire world.
My recent conversations on background with several high-ranking Ukrainian officials offer insights into these events. First, the retreat occurred amid U.S. worries that a humiliating defeat might provoke a Russian tactical nuclear response. Second, Ukraine was short of ammunition with the range to hit the river crossing, in part a result of Washington’s strict limits on the kind and amount of kit it supplied. Whatever the precise truth behind the Russians’ surprisingly unmolested retreat, which may remain a secret well after the war is concluded, the events around Kherson were emblematic of the way in which Ukraine’s hand has been tightly circumscribed throughout the war by the flow of U.S. and other Western weapons—and the restrictions placed on their use.
Joe Biden walks and Volodymyr Zelenskyi walk among a crowd.
Biden walks with Ukrainian President Volodymyr Zelensky in Kyiv on Feb. 20, 2023.Yan Dobronosov/Global Images Ukraine via Getty Images
President Donald Trump has often called the Russia-Ukraine conflict “Biden’s war.” Trump’s claim that former President Joe Biden is personally responsible for the invasion is, of course, wrong: Sole responsibility rests with Russian President Vladimir Putin—not Biden and not Ukraine, as Trump has also claimed. As most everyone except Trump seems to know, Putin has long questioned Ukraine’s legitimacy and has coveted its territory since at least 2014, when he launched Russia’s first land grab with the invasion of Crimea and occupation of the Donbas. Given the scale of Putin’s ambitions, it was only a matter of time before he launched a full-scale war.
But it is Biden’s war in a very different sense: To this day, the invasion has been largely shaped by the Biden administration’s decisions about when and how to arm Ukraine—and by the way the United States used military aid as leverage to constrain how Ukraine fights its war. These White House decisions, in turn, significantly determined the contours of Russia’s conquests. Ukraine’s current military posture, the territories it controls, and its high civilian and military casualties are all to a large degree shaped by the limits the Biden administration placed on how Ukraine could wage its war—limits which remain in place to this day.
To be sure, Biden’s Ukraine legacy is not only negative. Without his administration’s substantial support and his successful efforts at shaping an international coalition to support Kyiv, Ukraine likely would not have held on to some 80 percent of its territory. Nor could Russia’s advances have been slowed to a debilitating crawl. Had Trump been in power, he might have preferred business deals with Moscow rather than supporting Kyiv. Still, Biden’s excessive caution and tight constraints on how Ukraine could fight almost certainly contributed to the stalling of Ukraine’s rapid counteroffensives in the fall of 2022 and to the fact that, to this day, Russia feels little pressure to conclude the war and seek a settlement on any terms but its own.
Biden cared deeply about the fate of Ukraine and deserves huge credit for expertly shaping unity, burden-sharing, coordination of assistance, and cooperation among NATO allies and other democracies. Indeed, the strong solidarity European leaders have shown recently—and most dramatically in their meeting with Trump in the Oval Office on Aug. 18—is a legacy of Biden’s highly effective coalition building.
Leaders of European countries and Donald Trump gather around a large conference table in the White House.
U.S. President Donald Trump meets with Zelensky and other European leaders in the White House on Aug. 18.Andrew Caballero-Reynolds/AFP via Getty Images
But the failings of the Biden team and its excessive caution in aiding Ukraine’s military should not escape honest appraisal.
The first failing—a legacy of the Obama years, when Biden was vice president—was Biden’s refusal to significantly arm Ukraine over the course of the massive Russian military build-up on Ukraine’s borders that began in March 2021, just a few weeks into his administration. Despite Ukraine’s entreaties for new weapons to augment the anti-tank weapons provided by the first Trump administration, Biden did nothing.
Even after Washington prepared to send a modest $200 million dollar arms package, Biden dragged his feet on sending the assistance for fear of escalating tensions with Putin. According to an NBC News article from mid-December 2021, Biden decided to withhold the aid to “give more time for diplomatic efforts to defuse tensions.” The delay in aid thus continued for many critical weeks after U.S. intelligence had already concluded that Russia was preparing for a full-scale attack on Ukraine, according to a well-sourced report in the Washington Post. As a result of Biden’s delays, only a portion of the relatively meager aid package was transferred by the time Russia attacked in February 2022. Coupled with Biden effectively endorsing the Russo-German Nord Stream 2 gas pipeline and the humiliating U.S. withdrawal from Afghanistan, the Kremlin could not but see all of this as signaling Washington’s weakness and lack of resolve.
In the early stages of the war, moreover, the Biden team held back significant aid, since it was convinced that Ukraine’s forces would be rapidly defeated by the Russians. The administration’s faulty assessments were echoed by Samuel Charap, a Russia expert favored by Biden’s national security team, who argued in Foreign Policy that “The West’s Weapons Won’t Make Any Difference to Ukraine.” One high-ranking former official in Ukraine’s government who was party to conversations with the U.S. side told me that he believes that Biden’s reluctance was, at least in part, informed by the Taliban’s capture of U.S. weapons worth billions of dollars. Biden believed that Russia would quickly overrun Ukraine—and thus seemed to fear that the weapons could end up in Putin’s hands.
Reality proved far different. Anti-tank Javelins provided by the first Trump administration, anti-tank NLAWs from Britain, and Ukraine’s own arsenal (a mix of domestically produced weapons and Soviet-era equipment)—combined with the daring combat operations of highly motivated defenders under the command of Gen. Valery Zaluzhny—enabled Ukraine to overcome the odds and push Russia out of much of the territory it initially seized. Ukraine’s unexpected successes created an opening for the Biden administration and NATO allies to finally overcome some of their fears and ratchet up support.
Three Ukrainian troop members repair an army’s Main Battle Tank.
Ukrainian troops repair a tank in the eastern Ukrainian region of Donbas on June 7, 2022.Aris Messinis/AFP via Getty Images
Yet despite Ukraine’s major successes, Biden and his team failed Ukraine at virtually every turn during the war. They held back crucial weapons and, out of an overabundance of caution, severely restricted how Kyiv could conduct its fight for survival.
The Biden administration’s fears of nuclear escalation played a crucial role in shaping U.S. support in the years that followed. Aware of these fears, the Kremlin expertly stoked them with frequent threats—a textbook case of what Soviet-era strategists called “reflexive control,” a kind of psychological warfare designed to shape an adversary’s thinking. The Biden White House believed a variant of Obama’s theory of Russian “escalation dominance”—the idea that Russia could always escalate the conflict to negate any U.S. aid. Between 2014 and the end of Obama’s term in 2017, this theory was his justification for denying Kyiv any lethal U.S. military assistance.
While Russia may have contemplated the use of tactical nuclear weapons early in the war, this was a risk the Ukrainians were willing to take. After a year of fierce combat, significant Russian defeats on the battlefield (including large losses of occupied territory), and the delivery of new types of Western weapons deliveries, the threat of escalation—insofar as it ever existed—had receded. By then, all that remained was the persistent U.S. policy of restraining Ukraine’s effective prosecution of the war. The operation of that policy is revealed in Bob Woodward’s War, which reports an exchange on Oct. 21, 2022, in which Defense Secretary Lloyd Austin tells his Russian counterpart Sergei Shoigu: “We have taken care not to do certain things. … There are certain restrictions we’ve put on how they can use the stuff we’ve given them.” Austin’s phrase reveals the essence of the Biden approach to Ukraine’s war effort, a policy that remains in place to this day.
U.S. constraints continued even after there were strong indications from China, Russia’s main strategic partner, that Putin would not resort to the nuclear option. A high-ranking Ukrainian diplomat told me that the Chinese side had informed the Ukrainians that President Xi Jinping had clearly communicated to Putin that the nuclear option was impermissible. Given Putin’s growing dependence on Chinese support, this convinced Ukrainian officials that the Russians would not risk the use of nuclear weapons. Yet Washington consistently delayed, slow-walked, or outright opposed the transfer of key weapons that could have dramatically strengthened Kyiv in its conduct of the war.
By the end of January 2023, U.S. jitters about Russia’s supposedly imminent use of tactical nukes had partly abated. Ukraine’s impressive battleground performance in liberating Kharkiv and Kherson resulted in new Western commitments of weapons aid, including major battle tanks—even as many of the deliveries continued to be slow-walked. But Ukraine’s requests for deep strike weapons to hit military and logistics targets in the Russian rear remained unanswered, as they would throughout the Biden years.
A woman talks with Russian soldiers in downtown Mariupol, in eastern Ukraine, on April 12, 2022. Alexander Nemenov/AFP via Getty Images
Fresh graves with handwritten wooden signs.
Fresh graves at a cemetery in Mariupol on June 2, 2022. AFP via Getty Images
The historic record of the Biden administration’s unwillingness to properly arm the Ukrainians is striking. Initial Ukrainian requests for HIMARS multiple-rocket launchers were not answered until the summer of 2022, and they only came after the strategically important port city of Mariupol, with a population of roughly 450,000, had already fallen after a gruesome siege that left the city a smoldering ruin. Mass graves near the city indicate that Ukrainian civilian and military deaths may have numbered in the tens of thousands. Kyiv’s entreaties for Patriot air defense systems also went unanswered for most of 2022 despite sustained, brutal Russian attacks against civilian targets in Ukrainian cities. Why even purely defensive weapons were off-limits then remains Biden’s and then-National Security Advisor Jake Sullivan’s secret.
It took until September 2023, more than a year and a half after Russia’s invasion, for the first Abrams tanks to reach Ukrainian forces. And it was London, not Washington, that in May 2023 announced that it would supply long-range Storm Shadow missiles to Kyiv. U.S. deliveries of its own long-range missiles known as ATACMS began only in October 2023. Even then, these missiles were modified to limit their range and came with a restriction against their use against military targets on Russian territory. In the summer of 2024, for example, the Ukrainians begged to be allowed to strike one of Russia’s main bomber bases only 100 miles inside the border, only to have their requests denied. The restriction was partially lifted only in November 2024.
It also appears that the Biden administration pressured Kyiv not to strike certain Russian military and logistical targets even on its own sovereign territory. A New York Times report disclosed U.S. opposition to Ukrainian strikes on a Russian air base in Crimea and the Kerch Strait Bridge, a critical resupply link for the Russian military. The same article also mentions an undisclosed Ukrainian operation that the United States stopped at the Kremlin’s request.
What’s more, the Biden administration imposed its arbitrary red lines all throughout the war not only on itself and Ukraine, but also on European allies. These were held back from providing certain weapons, including tanks, long-range missiles, and European-owned F-16 fighters; once the restrictions were belatedly lifted, the fighters became a crucial element of Ukraine’s air defense against Russian attacks.
As the Hudson Institute’s Luke Coffey has written, “delays affected the provision of cluster munitions, tanks, infantry fighting vehicles and [ATACMS]. While the US eventually authorized all these systems, its indecision cost Ukraine dearly, forcing it to respond reactively instead of proactively.” In other words, Biden forced Ukraine to fight Russia with one hand tied behind its back.
A couple poses in front of an artwork showing the Kerch bridge with two explosions, shaped like a large postage stamp.
A couple poses in front of artwork depicting an explosion on the Kerch Bridge, seen in central Kyiv on Oct. 8, 2022.Sergei Supinsky/AFP via Getty Images
If limited U.S. aid was only enough to hold the Russians at bay, it did ensure that Ukraine survived as a state. In these circumstances, the Ukrainians slowly began the development and mass production of some of the weapons they were being denied, including their own long-range missiles. It also bought time for the emergence of a powerful combat drone industry that has transformed the battlefield.
Ukraine’s own innovations notwithstanding, Biden’s restrictions on targeting Russia meant that Ukraine had very limited ability to attack military and infrastructure targets inside Russia, such as the airfields used to launch bomber attacks. In 2024, the Biden administration even micromanaged the use of Kyiv’s own domestically produced weapons, pressuring Ukraine to halt its drone strikes on Russian oil refineries. It appears that the Ukrainians complied, shifting to strikes on fuel depots that created impressive explosions but little strategic impact. Under Trump, that restriction is gone, and Ukraine has launched a highly effective drone campaign against Russian refineries, with the result that much of Russia now faces fuel shortages. The success of this campaign also proves that hitting oil infrastructure was never the red line the Biden administration imagined it to be.
Biden’s restrictions made little military sense, and they created a stark imbalance. When Russian missiles and drones shut down electricity, heating, and water supplies in Ukrainian cities, Ukraine had little capacity to respond in kind. Russian attacks have continued unabated to this day, killing civilians and wiping out thousands of Ukrainian schools, churches, hospitals, apartment blocks, and offices. The one-sidedness of these attacks demonstrates the ongoing effect of Biden’s restrictions.
The Biden administration’s cautious approach left a political legacy in the United States as well. The deadlock in Ukraine created by the slow trickle of weapons and tight restrictions on their use raised the specter of another “forever war,” which contributed to growing opposition from Trump-adjacent Republicans and likely helped Trump during the 2024 election campaign.
Mindful of growing sentiment among MAGA conservatives to wind down U.S. support for Ukraine, Republican Reps. Michael McCaul, Mike Rogers, and Mike Turner issued a detailed report in January 2024 calling for weapons restrictions to be lifted, warning that the Biden administration had not developed a plan to secure an end to the war. The legislators charged that “[s]ince the first day of the war, Biden’s debilitating hesitation to provide critical weapons to Ukraine has delayed a Ukrainian victory.” They further argued that a path to victory for Ukraine “will require (1) providing critical weapons to Ukraine at the speed of relevance, (2) tightening sanctions on the Putin regime, and (3) transferring [$300 billion of] frozen Russian sovereign assets to Ukraine.”
Trump echoed this criticism when he posted on Truth Social in August 2025 that “Biden would not let Ukraine FIGHT BACK, only DEFEND. How did that work out?” These remarks notwithstanding, most Biden-era constraints on Ukraine’s war-fighting remain in place under Trump. Indeed, as the Wall Street Journal reported on Aug. 23, the Trump administration quietly blocked Ukraine from firing long-range ATACMS against targets in Russia. Even under the new U.S. policy requiring all weapons shipments to be fully paid for by Europe or Ukraine, most of these purchases remain severely restricted in type, quantity, and permitted use.
Had the Biden not imposed arbitrary red lines or let itself be manipulated by the Kremlin’s stoking of nuclear fears, Mariupol might not have fallen. Ukraine would surely have kept up the momentum of its 2022 counteroffensive, liberating much more of its territory before the Russians had a chance to dig in. Ukraine would have been able to inflict a humiliating defeat on the retreating Russians and their equipment in Kherson. It would have been able to destroy the Russian bombers and air bases used to bring nightly death to Ukrainian civilians. Russia’s oil and gas industry—the most important cash cow for the Russian war machine—would have been paralyzed. And the Kremlin might long ago have come to the negotiating table, forced to extricate itself from an unwinnable war.
Instead, Biden’s shaping of Ukraine’s war lives on under Trump. And while the latter deserves some credit for his vigorous attempts to push for an end to the fighting, he is unlikely to succeed, as the bungled efforts of his envoy, Steve Witkoff, show. Reaching a lasting peace will require forcing Putin to the bargaining table. For that to happen, Trump would first need to end Biden’s war by allowing Ukraine to more effectively fight its own. Such a war—sustained by European financing (including the use of frozen Russian reserves), enabled by the unconstrained use of U.S. and allied weapons (including the ability to strike targets in Moscow and St. Petersburg), and accompanied by strong secondary sanctions—remains the quickest path to bring the conflict to an end.
