This weekend marked a new escalation in the lingering conflict between Ukraine and Russia, as Moscow closed the Kerch Straight, a vital water route used both by Ukraine and Russia. Ukraine accused Russia of stopping three of its ships and seizing two. Six Ukrainian sailors were reported to be injured. Kiev subsequently pondered implementing martial law, a proposal Ukrainian lawmakers may pass on Monday.

Since Russia annexed the country’s peninsula, Crimea, in 2014, the United States has been among Ukraine’s strongest supporters, selling weapons and training soldiers.

But amid one of the most tense situations since 2014, the strongest condemnations came from somewhere else. In Brussels, the European Union urged Russia to “restore freedom of passage,” and NATO said it “fully supports Ukraine’s sovereignty and its territorial integrity."

Meanwhile, President Trump had a different message to the world Sunday: “Europe has to pay their fair share for Military Protection,” he wrote. “The European Union, for many years, has taken advantage of us on Trade, and then they don’t live up to their Military commitment through NATO. Things must change fast!”

Trump’s remarks were not new, and even though they show a misunderstanding of how NATO finances work, it is correct that many European nations still spend less on defense than the United States does. President Trump has previously suggested that the future of NATO might be tied to Europe’s willingness to spend more on defense.

Reprising his demands the same day NATO’s core rival — Russia — was accused of stirring new tensions appeared unprecedented, however.

“Russia provokes in the east, Trump attacks from the west,” wrote David Rothkopf, a former Clinton administration official.

Sunday’s tweet will play into the hands of Trump critics arguing that the president has been too lenient on his Russian counterpart. But it is also the latest incident that suggests the president is in large part focused on money, even in situations in which financial gains or losses are difficult to measure. While defense spending shortfalls in Europe are relatively easy to capture in statistics, the overall financial and humanitarian risks of an open confrontation with Russia are harder to predict — and could cost the United States far more.

Officials have faced similar dilemmas when trying to convince Trump that it is in the United States' strategic interest to be engaged in other conflicts, as well. This weekend, the news site Axios reported that Trump asked the Iraqi prime minister twice if he would compensate the United States for its wars with oil.

The idea that the United States invaded Iraq to access the country’s oil sources has often been put forward by conspiracy theorists and was always rejected by U.S. officials. Any U.S. attempt to seize Iraqi oil fields would have been a violation of international law. Yet Trump publicly pondered ways for the United States to access Iraqi oil both on the campaign trail and reportedly in conversations as president.

According to Axios, one source recalled former national security adviser H.R. McMaster explaining to Trump why that’s a bad idea: “We can’t do this and you shouldn’t talk about it. Because talking about it is just bad. … It’s bad for America’s reputation, it’ll spook allies, it scares everybody, and it makes us look like — I don’t remember if he used words this harsh — like criminals and thieves, but that was the point he was trying to get across."

Elsewhere, similar efforts to repay U.S. military spending through local resource extraction have been met with less resistance, however. Last year, the White House announced that U.S. companies would help Afghanistan extract rare minerals and specifically cited the possibility of job creation “in both countries, therefore defraying some of the costs of United States assistance as Afghans become more self-reliant.”

But what works in Kabul may not necessarily work in Baghdad — or Berlin and Paris, the president has had to learn. While Trump has at times linked Europe’s reliance on the U.S. military with what he says are unfair E.U. trade practices, European negotiators have taken pains to separate the two issues.

In fact, Trump’s stance has bolstered European voices in favor of catering less to U.S. demands.

“We have to have a Europe that can defend itself alone — and without only relying on the United States — in a more sovereign manner,” French President Emmanuel Macron said in an interview two weeks ago before the Kerch Straight incident.

More on WorldViews: