Winston Churchill and Franklin Roosevelt. Ronald Reagan and Margaret Thatcher. Tony Blair and Bill Clinton — and then George W. Bush. Reaching across the pond, and across the aisle, leaders of the United States and the United Kingdom have been stalwart stewards of their nations’ “special relationship,” which together has been the backbone in fights against fascism, communism and extremism. America and Great Britain need each other. And an increasingly chaotic world needs their combined moral, military and political power to try to restore order.

That fact made it especially disheartening to see Donald Trump become the subject of a lively Parliamentary debate over whether the front-runner for the Republican presidential nomination should be banned from entering Great Britain, the country of his mother’s birth. The debate was triggered by an online petition signed by more than half a million Brits who took offense to Trump’s call for a temporary ban on Muslims entering the U.S. That stance offended many in this country, of course, but also worldwide — and not just in the Mideast.

“He’s talking about me. He’s talking about my family, my children,” said Tasmina Ahmed-Sheikh, a member of Parliament. Indeed, there are Muslims living in all allied countries, and not just in the U.K. and Europe, but in bulwarks against terrorism such as India. Trump’s bombast also might alienate allies in Muslim countries counted on to fight the Islamic State of Iraq and the Levant, as rival candidates Jeb Bush and John Kasich were right to point out in the most recent GOP debate.

In the end, Parliament rightly backed away from barring Trump. After all, any country that’s home to the iconic Speakers’ Corner shouldn’t thwart free speech. Instead, members used the parliamentary platform for ridicule, an activity Trump routinely practices himself. But critics weren’t limited to offended members of Parliament. Even Prime Minister David Cameron, who would be a key partner for a President Trump, previously labeled the no-Muslims proposal as “divisive, stupid and wrong.”

Cameron is not the only European leader Trump may have offended. When Time magazine named German Chancellor Angela Merkel its 2015 “Person of the Year,” a piqued Trump tweeted: “I told you @TIME Magazine would never pick me as person of the year despite being the big favorite. They picked person who is ruining Germany.”

In its annual list of “top risks,” the Eurasia Group, a global political risk research and consulting firm, names “the hollow alliance” between the U.S. and European partners as its top concern, even ahead of ISIL. Bringing order to an increasingly chaotic world will take, and test, U.S. and European ties, which are already strained. Trump’s intemperate blurts and ill-advised ideas might further strain those bonds.

If Trump truly wants to deliver on his promise to “make America great again,” he should shore up transatlantic ties, starting with recanting his call for a temporary ban on Muslims entering the U.S.