European leaders and U.S. experts are confused and concerned about what they see as conflicting messages from the Trump White House about policy toward the European Union. They’re not sure whether the administration will support the union in its current form, or encourage more countries to leave it, potentially leading to its disintegration.

This week’s visit to Europe by Vice President Pence to reassure nervous allies contrasted with a series of other events that are calling into question the decades-long bipartisan U.S. policy of E.U. support. Suddenly, the previously fringe view that the European Union is bad for the United States has been thrust into the mainstream foreign policy debate in Washington, and those for and against that idea are gearing up for a battle that could help determine the future of the union and the transatlantic alliance.

“Too much has happened over the past month in your country and in the E.U. Too many new and sometimes surprising opinions have been voiced over this time about our relations, and our common security, for us to pretend that everything is as it used to be,” European Council President Donald Tusk said Monday as he stood alongside Pence in Brussels.