President Joe Biden’s recent decisions to allow Ukraine to launch missiles deeper into Russia and to provide Kyiv with controversial antipersonnel land mines were driven by a stark new reality: Russia’s importing of North Korean troops, Ukrainian battlefield losses and the election of Donald Trump have thrust Ukraine into perhaps its weakest position in nearly three years.

Many U.S. officials now concede that within a few months, Ukraine could be pushed into negotiations with Russia to end the war and that it could be forced to give up territory. Biden’s reversal of his previous policies on mines and missiles was intended in part to give Ukraine the strongest possible hand as it enters those potential talks.

The change of direction also caps a long-standing pattern, as Biden has often resisted upgrading Kyiv’s weaponry for fear of escalation with Russia, only to relent a few months later. The most recent reversals are drawing both praise and criticism from European allies, who say Ukraine needs every advantage in the coming weeks but are frustrated that it took the president until now to provide the capabilities.

Biden’s lame-duck push to pull out all the stops to help Ukraine has renewed a long-standing question among some U.S. and European officials: Why was the assistance not granted earlier, when it might have bolstered Ukraine when its position was more robust, rather than providing a backfill at a moment when Kyiv appears to be flagging?

Kurt Volker, who served as U.S. ambassador to NATO under President George W. Bush and was Trump’s special envoy to Ukraine, said the changes were “long overdue” and that Biden may have emboldened Moscow by not sending more powerful weapons earlier. “It gives Russia a sense of impunity,” Volker said. “They know they have a sanctuary. They know we don’t want to escalate, and they can go ahead and carry out the war, conduct strikes and do outrageous things.”

But Biden has been keenly sensitive to the risk that Russian President Vladimir Putin might dangerously escalate the conflict, potentially using nuclear weapons, if he felt threatened. White House officials say Biden’s decisions have been guided by evolving battlefield conditions, authorizing weapons when those conditions warrant. And they note that Biden has provided many weapons - including cluster munitions, artillery shells and air defense systems and missiles - without Ukraine lobbying or in some cases even asking for them.

The discussions about authorizing the land mines and longer-range Army Tactical Missile Systems, or ATACMS, began in late October, but no decisions were finalized until after the election, according to two senior administration officials, who spoke on the condition of anonymity to detail private conversations.

U.S. officials are especially worried about North Korea’s decision to deploy some 10,000 troops to help Russia, and the possibility that the number could grow. And they are concerned that as Ukraine shifted troops to the hard-fought Russian Kursk region - which Kyiv took in August - it is losing territory in its east at a faster clip. Top Biden aides ultimately concluded that the ATACMS, which have a range of about 190 miles, could help deter North Korea from sending more troops and that the land mines could help Ukraine defend territory in its east.

Trump has vowed to end the Russia-Ukraine war, which began when Russia invaded in February 2022, within 24 hours, though he has not specified how he would do so. With the current tranche of U.S. military and economic aid to Ukraine set to run out sometime next year, Biden officials have largely resigned themselves to the likelihood that Trump will not provide Ukraine more assistance once he takes office.

In all, the current dynamics suggest that one of Biden’s biggest foreign policy accomplishments is increasingly under threat. Biden declared in 2022 that Putin “cannot remain in power,” but it now appears likely that Putin’s gamble that he could outlast Western support for Ukraine could come to fruition, as he will soon face a U.S. president far more sympathetic to his position.

Biden has been praised for much of his handling of the war, including his decision to declassify intelligence showing that Russia planned to invade Ukraine; his leadership of a Western alliance that bolstered Kyiv with aid and weapons; and his oversight of an expansion of NATO. But he has also been criticized by some allies for being too slow to provide Ukraine with the advanced weaponry it has asked for, with ATACMS as the latest example.

The controversial decision to send antipersonnel land mines - a weapon that many countries renounced years ago for humanitarian reasons - showed just how urgently the White House sees the situation, U.S. officials said.

Throughout the war, Biden’s concern that Putin might react recklessly to an act he considered provocative, even using nuclear or biological weapons, has at times put him at odds with some of his top advisers.

“There’s no doubt that on every big issue - ATACMS, F-16s, attacking Russian targets inside Russia - Biden was alone,” said Ivo Daalder, former NATO ambassador under President Barack Obama and president of the Chicago Council on Global Affairs. “He was deterred by the prospect of an escalation with Russia. His Cold War view was, the one thing you want to avoid at all costs is a direct military confrontation between the United States and Russia.”

Biden, who is 82, has spent more than 50 years steeped in foreign policy and came into office with established views on key issues, including Russia. Much of the president’s worldview was shaped during the Cold War, when the Soviet Union was a global superpower engaged in a nuclear arms race with the United States, an outlook foreign to many of his younger advisers.

Biden has been dedicated to Ukraine’s defense, expending significant political capital to mobilize tens of billions of dollars of economic and military aid. He has encouraged European countries to do the same, even as the war has rocked the global economy and led to higher gas and heating costs, often framing the conflict as a pivotal battle between authoritarianism and democracy.

But Biden’s fear of escalation with Russia has also factored heavily into his decisions to limit the weaponry provided to Kyiv. That fear has often been bolstered by U.S. intelligence agencies; analysts concluded that the powerful ATACMS, for example, might goad Putin into a dramatic response, according to two senior administration officials. Biden ultimately allowed the ATACMS to be used inside Russia after North Korea sent troops to aid Moscow, hoping to send Pyongyang a message that it risked suffering significant casualties.

It was not the first time he had hesitated to upgrade Kyiv’s firepower. Biden initially hesitated to provide M1 Abrams tanks, concerned that they would be too logistically burdensome for Ukrainian troops. Amid urgent pleas from Ukrainian President Volodymyr Zelensky, Biden ultimately agreed to provide the tanks in January 2023. Similarly, Biden initially concluded that Ukraine did not need F-16 fighter jets, but in May 2023 the president relented, paving the way for Kyiv to receive the planes, which Zelensky desperately wanted.

Biden’s aides say the president has shown appropriate caution, given the unpalatable risk of a nuclear conflict, and they say his decisions have been driven far more by policy than fear of escalation. The aides downplay the notion that providing the weapons earlier would have significantly affected the course of the war.

Many European officials disagree strongly, saying the United States has done just enough to let Ukraine keep fighting, but not enough to allow it to prevail.

The antipersonnel land mines in particular - simple, low-cost devices that self-destruct or lose battery charge to render them inactive within days or weeks - could have helped Kyiv bolster its defensive lines in a war where Russia has seeded its own lines inside Ukrainian territory with millions of land mines, all but halting Ukrainian advances, these officials said.

“It’s two years too late,” one senior European official said earlier this month about the decision to send the land mines.

Yet even those who disagree with Biden’s decisions say they recognize the pressure he is under to ensure the United States does not become enmeshed in a broader war with a nuclear-armed adversary.

In September 2022, when Ukraine was far exceeding expectations on the battlefield, Washington had intelligence that the Kremlin was contemplating the use of nuclear weapons, according to three people familiar with the situation, who spoke on the condition of anonymity to discuss confidential information.

Those intelligence reports were a backdrop for a decision by Biden a few months later to reject a proposal from Secretary of State Antony Blinken and national security adviser Jake Sullivan. In a meeting in the Oval Office, Blinken and Sullivan suggested warning Russia that if it did not stop shooting missiles and drones at civilian targets, the United States would provide Ukraine ATACMS.

Biden resisted, worried about how Russia would react, and he only relented - partially - nearly a year later, when he agreed to provide Ukraine with medium-range ATACMS in the fall of 2023. The longer-range ATACMS came even later, in the spring of 2024.

Ukrainian leaders have repeatedly complained that America’s habit of saying no when they ask for advanced weapons, only to say yes a few months later, makes the weapons less effective than if they were sent when initially requested. Inside the administration, the Ukrainian requests have often opened divides, with Blinken and the State Department frequently more comfortable granting them than Biden or the Defense Department.

State Department officials have at times said they are confident Putin’s threats are a bluff. The intelligence community, they contend, tends to raise alarms about dire consequences if Ukraine gets more assistance, but then when the aid has actually been provided, those scenarios have failed to materialize.

When Ukrainian leaders requested permission over the summer to use the longer-range ATACMS missiles to strike into Russian territory, State Department officials were quickly on board. But the Pentagon and White House were opposed, partly because of escalatory concerns and partly because the Pentagon worried about Ukraine’s dwindling stock of the advanced missiles, officials said at the time.

At the same time, British officials could not let Ukraine use its Storm Shadow missiles against Russian territory, even though they wanted to, because U.S. components in the British missiles gave the White House a veto - and in any case, they wanted to coordinate with the United States. Biden’s decision to allow Ukraine to use ATACMS inside Russia freed Britain to make the same move.

As part of an effort to “Trump-proof” aid to Ukraine, European and NATO policymakers pushed through aid packages ahead of the U.S. election and moved some coordination of military aid from U.S. hands to a new NATO command. But Trump’s comeback has renewed questions about the ability of European nations to defend Ukraine without American help.

Once taboo, a quiet recognition is spreading among Kyiv’s European backers that peace negotiations may require Ukraine to give up some territory to Russia. They are now contemplating what security guarantees Ukraine might receive in return to deter Russia from future attacks.

Blinken made a one-day visit to NATO headquarters earlier this month, and European officials said he brought one central message:

“We’re going to do everything we can to reinforce Ukraine before Trump takes office, and you guys should do the same.”

previous coverage

• Ukraine says Russian attack sets a new record for the number of drones used