EUROPE and America have been slowly drifting apart for millions of years. Tectonic shift means that the physical distance between the continents grows by about an inch every year. If only the political divergence were so languid. From NATO to Donald Trump’s travel ban to accusations of currency manipulation, the gap between once-strong allies on either side of the Atlantic has rarely felt as chasmic.

Relations may get frostier yet. On March 2nd, the European Parliament voted temporarily to suspend visa-free travel for Americans visiting the EU. The vote is not binding—it will be up to the European Commission, the body's executive arm, to decide whether to implement the recommendation. Nonetheless, the decision marks a sad state of affairs.

The main reason for the vote is the way that travellers from some EU countries are treated by America. While most citizens of EU countries can travel to the United States without a visa, those from Bulgaria, Croatia, Cyprus, Poland and Romania must still obtain one. Because the EU demands equal treatment of all its citizens in such matters, it says it is legally obliged to fight back.

Some media outlets, including Fox News, suggest that the move is a reaction against Donald Trump. It is true that the EU and the 45th president are not members of a mutual admiration society. Mr Trump, after all, was full of praise for Brexit. (He later described the European Union “wonderful”, although that may have been ironic.) EU leaders, meanwhile, have been mostly united in their condemnation of Mr Trump's attempted ban on immigrants and travellers from seven Muslim-majority countries. But the visa dispute is much older than the Trump administration. (See Gulliver from April 2016.) The EU says it notified the United States in April 2014 that it was not meeting EU visa rules, and had given the country two years to comply. (Canada was also put on notice, and has since changed its policy.)

Americans need not start queuing at the French embassy just yet. Implementing the parliament’s recommendation would require the agreement of all EU members, which would probably take years. But there does seem to be genuine annoyance among eurocrats that America is refusing to treat EU citizens equally. America might reasonably reply that the EU is not a state, and that the United States has the right to impose whatever restrictions it likes on individual countries.

It is to be hoped that pragmatism will prevail. Donald Trump does not seem like the sort of president who would back away from a visa war, should it come to that. Given the mutual flow of tourists and trade—not to mention an historic friendship—both sides would lose.