If the Turks crush Syrian Kurdish forces this weekend, how should we react? You can say that these Kurds are our allies, who risked and gave their lives confronting Islamic State jihadists not so long ago. That decent countries defend their friends, and we should act. Or you might argue that there’s been too much Western “acting” of late, costing billions and achieving nothing. So best leave the Kurds to fight their own battles.

I’m in the former camp. When Sir John Major’s government decided to defend the Iraqi Kurds with a no-fly zone in 1991 – in effect, protecting them from Saddam’s butchery – it led to stability and even prosperity. We ended up with good relations, trade, even Land Rover dealerships in Irbil. And we exchanged people. The page you’re reading was designed by Kuchar Swara, a Kurd who also redesigned The Spectator. Business minister Nadim Zahawi is another Kurdish export. The Kurds have long been Britain’s friends. And America’s, too.

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But Donald Trump is redefining alliances now. The Kurds didn’t fight in Normandy, he bizarrely said this week, so why should America shield them from the Turks? Or shield anyone in the region from anyone? “The worst mistake the United States has ever made, in my opinion, is going into the Middle East,” he said. He puts the cost of deployments in Afghanistan, Libya and Iraq at anything from $4 trillion to $8 trillion, depending on his mood and his audience. His upshot: he’s fed up with America being the world’s policeman. He’s walking away from the role, and his allies will have to get used to it.