Without US aid, Ukraine would lose some of its most sophisticated weapons
Kyiv could find itself short of ammunition and unable to use some weaponry as soon as the summer if President Trump cuts off U.S. supplies.
KYIV—Without U.S. military aid, Ukraine has enough weapons to keep fighting at its current pace until the summer, current and former Western officials said. After that, Kyiv could find itself short of ammunition and unable to use some of its most sophisticated weaponry.
President Trump’s broadsides against Ukrainian President Volodymyr Zelensky in recent days are forcing Kyiv to confront the prospect of losing U.S. military support, which has been instrumental in helping it hold off Russian forces over three years of war.
Large weapons shipments the Biden administration sent or contracted for in its final months should be enough to enable the Ukrainians to keep fighting at their current rate at least until the middle of the year, said Celeste Wallander, a former senior Pentagon official. Some Ukrainian analysts say their country might be able to eke the weapons out even longer.
“We can endure maybe half a year or a year, in order to give Europe another year to start producing whatever munitions they can," said Mykola Bielieskov, a senior analyst at Come Back Alive, a Ukrainian charity that has supplied drones to the military. “We might suffer some losses, maybe lose some territory. But we have no choice but to fight, despite the difficulties."
An end to U.S. military aid is the worst-case scenario, said a senior aide to Zelensky, adding that it would mean Ukraine having to build up its military production and get more from Europeans.
Europe is preparing to try to make up the shortfall. In 2024, the European Union, the U.K. and Norway collectively supplied Ukraine with around $25 billion in military aid—more than the U.S. sent that year, according to European officials. The continent has substantially increased its production of artillery shells, and there are discussions for the EU to increase aid to $30 billion this year.
Since the start of Russia’s full-scale invasion of Ukraine, the U.S. has sent nearly $70 billion in military aid, according to Zelensky. That is more than all of Ukraine’s other Western allies combined, according to the Kiel Institute for the World Economy.
But Ukraine has also built its own formidable munitions industry, which now produces $30 billion a year in weaponry, according to the country’s minister of strategic industry, a sixfold increase from a year earlier. In 2024, the country produced around 1.5 million drones, which have become its primary form of defense along the front line, allowing Kyiv to hold off Russian assaults while taking minimal casualties. This year, officials say, they plan to produce 3,000 missiles and 30,000 long-range drones.
Overall, Ukraine currently builds or finances about 55% of its military hardware. The U.S. supplies around 20%, while Europe supplies 25%, according to one Western official.
But some U.S. supplies—including advanced air-defense systems, surface-to-surface ballistic missiles, navigation systems and long-range rocket artillery—will be effectively impossible to replace in the short term. Europe simply doesn’t make enough—or, in some cases, any.
Once those U.S. supplies run out, Ukraine’s ability to conduct longer-range strikes, and to protect its own rear positions, would suffer, officials and analysts said.
“Having a partner who supplies you with the highest quality military technologies, it’s by definition irreplaceable in some areas," said Tomas Kopecny, the Czech governmental envoy for Ukraine’s reconstruction.
But the specter of an end to U.S. aid has loomed for more than a year now. During the campaign, Trump repeatedly criticized the billions sent to Kyiv, and many Republicans in Congress opposed the most recent aid package for Ukraine, which was approved last April.
Before leaving office, former President Joe Biden tried to enable Ukraine to keep fighting for as long as possible. His administration sent weapons from existing U.S. stocks and signed contracts with the U.S. defense industry to procure ammunition, air-defense interceptors, vehicles and other materiel. Those deliveries will continue into 2026.
“This was in support of what we understood the strategy of the incoming administration to be: To negotiate from a position of strength and lay out for Putin that the Ukrainians can continue to fight," said Wallander, the former Pentagon official, who served as an assistant secretary of Defense in the Biden administration.
Trump has now upended that assumption, attacking Zelensky in a series of posts on social media. He has accused the Ukrainian president of starting the war and called him a dictator. Both claims echo Kremlin talking points about the Ukrainian leader and the war, which began when Russia invaded the country in 2022.
Following Trump’s statements, Speaker of the House Mike Johnson also said there was “no appetite" in Congress for another Ukraine aid bill. But Vice President JD Vancetold The Wall Street Journal that the U.S. could use economic sanctions and even “military tools of leverage" to advance peace negotiations between Russian President Vladimir Putin and Zelensky.
Trump has inherited the authority to send more than $3.8 billion in arms to Ukraine from Pentagon stocks without Congressional approval, though administration officials would likely ask lawmakers to replenish the U.S. inventory should such a decision be made.
European leaders have held a series of meetings over the past week to plan how they can support Ukraine if the U.S. withdraws. The continent has also supplied some of Ukraine’s most effective weapons, including much of its modern artillery, medium-range air defense and cruise missiles. Still, analysts have questioned Europe’s ability to completely fill the gap created by lost U.S. supplies.
“While Europe could theoretically match the U.S. in spending, I don’t see them able to match the full breadth of weapons systems needed and, in certain critical categories such as air defense interceptors, there will quickly be a quantity problem," said Oscar Jonsson, an academic at the Swedish Defense University.
Ukraine now makes 2.5 million artillery and mortar rounds a year, according to Ukrainian officials. As of September, the U.S. had sent roughly three million artillery shells to Ukraine since the start of the invasion. The EU, by comparison, increased production of artillery shells to 1.4 million in 2024 and is aiming for two million this year.
The biggest challenge, according to analysts, would be the lack of American-made air defenses, which would leave Ukraine to decide which of its areas to protect and which to leave at risk. For example, only the U.S. produces Patriot air-defense systems, which can shoot down Russian ballistic missiles.
The loss of the U.S.-made Army Tactical Missile System, known as ATACMS, would also be a blow. Its range of up to 186 miles has made it particularly effective at striking Russian supply lines, though the Biden administration restricted the targets they could strike inside Russia.
Some analysts also questioned whether Ukraine would continue to have access to SpaceX’s Starlink internet service—a key battlefield advantage, which has been partly funded by the Pentagon. Elon Musk, the CEO of SpaceX, is a close ally of Trump.
Mykhailo Samus, director of the New Geopolitics Research Network, a Kyiv-based think tank, said it was possible that the U.S. could stop sending aid but still allow Europe to purchase American weapons on Ukraine’s behalf.
“It’s not really about aid—it’s about whether Trump will participate in the production of weapons for Ukraine," he said. If not, “this will be a categorical blow to Ukraine and to Europe."
Write to Michael R. Gordon at michael.gordon@wsj.com, Alistair MacDonald at Alistair.Macdonald@wsj.com and Ian Lovett at ian.lovett@wsj.com
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