Trump’s pause on Ukraine aid is like the U.S. switching sides in WWII, expert says

LONDON — President Donald Trump’s decision to pause American military aid to Ukraine is handing Russia's Vladimir Putin the upper hand on the battlefield and on the world stage, former officials and experts warned Tuesday.

Two White House officials said the defense assistance was being reviewed to make sure it was contributing to the administration's goal of being “focused on peace.”

As well as likely crippling Ukraine's military efforts, pulling the plug will deepen the chasm between the Trump administration and Washington's longtime European allies, who are already scrambling to fill the void left by a U.S. government's rapprochement with Moscow.

Michael McFaul, Washington’s former ambassador to Russia under President Barack Obama, said pausing Ukraine aid was akin to President Franklin D. Roosevelt losing “the 1940 election to an America Firster who then had the U.S. switch sides in World War II ... We’d all be speaking German now.”

“That’s why this current moment feels like," he wrote on X. “Three years into a war between an imperialist dictatorship with autocratic allies and a democracy, Trump just switched sides.”

The knock-on effects will be no less stark on the battlefield.

Ukraine has managed to slow Russian advances over the winter, thanks to it achieving parity with the level of Russian artillery on the front lines, according to Rob Lee, a senior fellow at the Foreign Policy Research Institute, a Philadelphia-based think tank.

It receives some ammunition from Europe, but "uncertainty about future U.S. aid shipments could lead Ukraine to begin rationing ammunition," he told NBC News, and ultimately "will lead to higher casualties for Ukrainian forces."

In the skies, Ukraine relies on the U.S. to supply the interceptor missiles for its Patriot air defense systems. "Without them, Ukraine will have more difficultly protecting its cities from Russian missile strikes," Lee said.

It also has no effective replacement for the multiple guided missiles, which the U.S. supplies for its High Mobility Artillery Rocket System, or HIMARS, which have been used to great effect against Russia.

Added to that, "Ukraine already faces a manpower shortage, so the loss of U.S. aid will pose greater challenges for Ukraine," Lee said.

The decision to pause aid comes after a meeting between Trump, Vice President JD Vance and Ukrainian President Volodymyr Zelenksyy descended into a shouting match Friday. Trump and Vance berated Zelenskyy that he hadn’t shown enough gratitude for Washington's $65.9 billion in military aid to Ukraine since 2022.

That's far more than any other country (the second highest is Germany's $13 billion, according to the Kiel Institute think tank.) In fact, the U.S. contributions are so large that they roughly equal all other nations’ aid put together.

Ukraine’s European allies do not see arming Ukraine as altruistic.

Instead, they see the war as the front line of a wider conflict already raging between Russia and the West, one that Putin will only seek to expand — possibly into other European countries — if he emerges with a win in Ukraine.

Cutting aid to Ukraine would not achieve a “sustainable peace” that Trump and his team say they want, so this argument goes, but rather allow the Kremlin to regroup ready for its next aggression — knowing that the U.S. no longer has the appetite to punish it.

“Cutting the current flow of aid to Ukraine would directly undermine President Trump’s stated goal of achieving a sustainable peace in Ukraine,” according to an analysis the Institute for the Study of War, a Washington defense think tank, published Monday before the news came through.

Though Russia has been making slow battlefield gains, American weapons have been allowing Ukraine to inflict “unsustainable losses on Russian forces while holding them to marginal gains,” the institute said. This “offers the United States great leverage in peace negotiations,” it added, warning that “a suspension of ongoing U.S. military assistance to Ukraine would encourage Russian President Vladimir Putin to continue to increase his demands and fuel his conviction that he can achieve total victory through war.”

The realization that Washington is no longer a willing security partner in Europe has prompted some leaders, most recently Germany's next likely leader, Friedrich Merz, to vow that their continent must be fully independent from their current American benefactors.

Trump has gained some credit in Europe by urging its leaders to spend more on defense. But this good has been somewhat undone, many experts say, by the president’s suggestion that he would not defend NATO allies, leaving them more at risk to Russian attack.

While news of Trump's Ukraine aid hiatus was reverberating across Europe, one of the continent's leaders, European Commission President Ursula von der Leyen, set out proposals that could raise some 800 billion euro in defense spending (around $840 billion) — almost double European's collective annual defense budget.

"We are living in the most momentous and dangerous of times," she said in a speech. "I do not need to describe the grave nature of the threats that we face. Or the devastating consequences that we will have to endure if those threats would come to pass."

This article was originally published on NBCNews.com