The British have demurred, the French are noncommittal and the Germans on Wednesday flat out said no. They’re all still smarting from the president’s exit from the 2015 Iran nuclear deal, which they say is partly responsible for Tehran’s suspected bellicose behavior. They’re also worried that aligning with the U.S. on such an initiative could drag them into a war with Iran. Those concerns have only risen this week after Trump imposed sanctions on Iran’s foreign minister.

“Clearly, a military operation in the Gulf would increase exponentially the potential triggers for a confrontation with Iran,” Nathalie Tocci, special adviser to European Union foreign policy chief Federica Mogherini, said via email. “So long as [Europeans] see a chance of freedom of navigation being secured through dialogue and diplomacy with Iran, they will opt for this route.”

“Other governments aren’t sure where the U.S. is trying to take them,” added Jon Alterman, a Middle East analyst in Washington. “They think that aligning with the U.S. incurs risk without providing security.”