Speaking to top NATO and European Union military brass gathered in Paris Tuesday, Dutch Defense Minister Ruben Brekelmans stressed the urgency of boosting Europe’s defense. While the transatlantic alliance is important, he said Europeans can no longer take U.S. protection for granted.

“Europe therefore needs to fortify its security architecture. And we don’t have much time to get this right. We only have one shot,” said Brekelmans.

The same message came from European Commission chief Ursula von der Leyen at the European Parliament.

“We need a surge in European defense, and we need it now,” she said.

The European Union’s executive arm has proposed an $873 billion plan for rearming Europe and supporting Ukraine. It includes relaxing fiscal rules and some $164 billion in loans for defense investments. It has proposed increasing defense spending by an additional 1.5 percent of member states’ GDP yearly over four years.

The proposed surge comes as Washington’s priorities appear to be shifting. And European leaders are worried Russia may not stop at Ukraine — fears their populations appear to share.

One Ipsos survey found three-quarters of French and half of Germans are concerned the Ukraine conflict will spread elsewhere in Europe. Another poll, however, found few Europeans want to pay more for defense.

Critics, including Hungary’s Viktor Orban, suggest Europe can’t afford to defend Ukraine. Others argue Brussels is assuming too much power.

Europeans are also divided over whether to invest in their own defense industry — or buy externally. The U.S. has been a top supplier.

Former French Ambassador Michel Duclos said, “They want to continue to sell weapons to European counties.”

Duclos is now an analyst at the Montaigne Institute research group in Paris. That’s one argument, he believes, for Washington’s at least short-term commitment to Europe’s security.

“What I fear more is not that they [the U.S.] will disengage. It’s more that they will want the Europeans to pay more and more for European protection,” he said.

This week sees more high-level meetings on Ukraine and European security. There’s another in Paris Wednesday, gathering Europe’s five top military powers, along with NATO and Ukrainian defense chiefs.