Donald Trump’s decision to slap tariffs on countries that have shown support for Greenland is pushing transatlantic relations to a breaking point as EU leaders contemplate ways of retaliating against Washington that until now have been unthinkable.

Relations between Washington and Europe have been rocky for months as the U.S. president has wavered on support for Ukraine, pressured EU countries into accepting a lopsided trade deal and forced NATO allies to massively ramp up their spending on defense. 

Even at the height of those tensions, EU leaders stopped short of hitting back — arguing that the risk of having the United States pull out of NATO was greater than any bad trade deal.

But now, as Trump ramps up his claims on Greenland, sparking protests over the weekend in the streets of Nuuk and Copenhagen, European leaders are facing increasingly loud calls to drop their softly-softly approach and prepare for confrontation. The fact that Trump triggered his tariffs just after the EU signed a major trade deal with Latin American countries is only deepening the sense of resolve among some Europeans.

“I’m convinced that we must not give in,” said Jérémie Gallon, a former French diplomat and current senior managing director at McLarty Associates, an international strategic advisory firm based in Washington. “Resisting a new attempt at humiliation and vassalization is the only way Europe can finally assert itself as a geopolitical actor.”

One option being floated by centrist and left-wing politicians is for Europe to wheel out its Anti-Coercion Instrument, the EU’s so-called trade “bazooka” — a powerful trade retaliation tool that was originally conceived to fend off bullying from China and that would allow Europe to impose tariffs and investment limits against offending nations.

“The EU should be prepared to deploy targeted and proportionate countermeasures,” Valérie Hayer, head of the centrist Renew Europe group in the European Parliament, posted on X late Saturday. “The activation of the EU Anti-Coercion Instrument should be explicitly considered, as it was designed precisely for situations of economic intimidation of this nature.”

In an X post of his own, French President Emmanuel Macron — who belongs to the same party as Hayer — did not explicitly endorse that call but hinted at potential retaliation by saying that Europeans would “respond in a united and coordinated manner should they [Trump’s tariffs] be confirmed.” 

The European Parliament is already poised to take action by blocking the ratification of an EU-U.S. trade deal agreed on last summer, after conservative party chief Manfred Weber said on Saturday that it was “not possible at this stage” to approve the deal.

But triggering the Anti-Coercion Instrument would be a much bigger step as it would mean deploying a tool originally designed for unfriendly states against the EU’s biggest ally and main benefactor of NATO. The fact that it’s now being openly discussed — amid unprecedented deployments of European troops to Greenland — speaks to how seriously Europeans are taking Trump’s claims on the island, which has been part of the Kingdom of Denmark for hundreds of years.

Gallon added: “If Europe finally wants to regain the respect of its own citizens and from the rest of the world, then it has no other choice.”

Keep calm, carry on

Even so, export-oriented European countries may well balk at the prospect of triggering a full-blow trade dispute with the United States over Greenland, an island with a population of 57,000 that voted to leave the EU’s predecessor, the European Community, in 1985.

Speaking to Deutsche Welle on Saturday, EU Trade Commissioner Maroš Šefčovič said it would be “very complicated” to approve the EU-U.S. trade deal in light of the current tensions, but made no mention of deploying the Anti-Coercion Instrument.

“What I just would like to highlight is the fact that that this [Mercosur trade agreement] should help us more than offset the negative consequences from the increased tariffs imposed by the United States,” Šefčovič told the outlet.

The new U.S. tariffs could trigger a “very dangerous downward spiral” — one that EU leaders should “simply avoid.”

With European ambassadors set to convene on Sunday for an emergency meeting to discuss how to respond to the latest tariffs, one EU official told POLITICO that the appetite for such a blow-up was likely to be much lower in the capitals than it is in the European Parliament, where politicians face pressure from their voters.

The ambassadors “will have a very different modus operandi,” said the official, who was granted anonymity to discuss sensitive internal deliberations on trade policy. “It’s rare that the European Parliament and Council are fully aligned, especially on a matter like this.”

Europe’s strategy in responding to Trump’s Greenland threats was in the process of being elaborated in the early hours of Sunday, as European Commission President Ursula von der Leyen, European Council President António Costa and their top advisers traveled back to Brussels from Latin America, where they just signed the Mercosur trade deal.

As they plot a path forward, leaders are likely to be guided by the bloc’s long-term economic and security interests, namely preserving NATO while building up Europe’s ability to become self-sufficient on defense in the medium term. In keeping with this approach, von der Leyen last week announced a new security strategy for the European Union, while the bloc is also due to unveil new plans to bolster its cybersecurity this week.

But even the most sanguine observers of EU-U.S. relations admit that the current moment is unprecedented and fraught with peril for the transatlantic alliance.

“It’s a scary time,” the EU official said. “We need to keep calm and keep moving.”

Gabriel Gavin, Zoya Sheftalovich and Max Griera contributed reporting.