Small explosive drones might be the most visible weapons in Russia’s three-year wider war on Ukraine, but the war—like every other major conflict since the start of the industrial age two centuries ago—is still mostly an artillery war.

Which is why substantial U.S. donations of artillery and artillery shells by the administration of then-President Joe Biden were critical to Ukraine’s self-defense for the first two years of the war. And why the cessation of aid, under current President Donald Trump, is so vexing to friends of a free Ukraine.

Ukraine “needs lots and lots of 155-millimeter shells,” wrote Michael Shurkin, an associate fellow at the Royal United Services Institute in London. Can Ukraine keep its big guns firing as Trump aligns the United States with Russia and halts further U.S. aid to Ukraine?

Fortunately for Ukraine, the answer is a qualified—and complicated—yes. Separate Czech, Estonian, German and Norwegian initiatives, among others, should keep Ukraine’s best 155-millimeter howitzers blasting away, even as stockpiles of American shells run out.

Since February 2022, Ukraine has received around 900 155-millimeter howitzers from its allies as well as millions of shells for these towed and self-propelled guns, each of which lobs a 100-pound shell 15 miles or farther. The Ukrainians have lost around 200 of the guns to Russian action, but are replacing them with locally made wheeled howitzers at a rate of around 20 new guns a month.

All told, Ukrainian artillery fires 5,000 or more 155-millimeter rounds every day for an annual total of around 2 million shells. That’s fewer shells than Russian artillery fires, but enough to shatter attacking Russian formations—and make them pay dearly in troops and vehicles for every yard they advance.

Under Biden, the United States donated more than 3 million 155-millimeter shells, many of them straight from the main U.S. Army shell factory in Pennsylvania, which has been ramping up production from a per-war rate of 14,000 155-millimeter rounds a month to a new target of 100,000 rounds a month.

But amid the Trump administration’s attempts to extort Ukraine’s mineral wealth and a disastrous Oval Office press conference on Friday, in which Trump and Vice President J.D. Vance berated a bewildered Ukrainian President Volodymyr Zelensky for not being sufficiently grateful for past U.S. aid, the White House is threatening to completely shut off munitions shipments that have already slowed to a trickle since Trump assumed office in January.

As a visibly shocked Zelensky left the White House on Friday, Ukraine’s European allies voiced their support for the wartime leader. “Ukraine can rely on Germany—and on Europe,” wrote German Chancellor Olaf Scholz.

It’s true, especially as Scholz steps aside and Chancellor-elect Friedrich Merz forms the next German government following his party’s electoral victory last week. Merz has vowed to lead Europe away from reliance on an increasingly autocratic United States and toward “strategic independence.”

Germany has shipped nearly half a million 155-millimeter shells to Ukraine—and is expanding domestic shell production in order to sustain supplies through 2025. More importantly, German arms manufacturer Rheinmetall has partnered with a Ukrainian firm to build a new factory for 155-millimeter shells in Ukraine—one that should begin producing hundreds of thousands of rounds annually starting next year.

That factory will join an existing Ukrainian factory, supported by Norway, that is already churning out 155-millimeter shells—albeit at a much lower rate.

For the next couple of years, however, Ukraine will continue to mostly rely on imported artillery ammo. As U.S. aid ends, the biggest sources of shells will be parallel Czech- and Estonian-led initiatives that scour the globe for 155-millimeter rounds and may have even sourced some of them from Indian and South African factories. South Korea is also a major producer of shells and has sold large batches to the United States for onward transfer to Ukraine.

The Czech initiative delivered 1.5 million shells last year and will continue unless and until the current government loses reelection to pro-Russian parties later this year. The Estonian initiative is just spooling up—and aims to ship 1 million shells in 12 months.

It’s all a logistical mess, but the bottom line is that Ukraine and its allies have established redundant supply lines for critical artillery and associated ammunition.

The Americans may quit the war. But that won’t prevent Ukraine’s biggest guns from firing away for the foreseeable future.