“Game, set and match to the President.” That’s the verdict of ConHome’s resident Boris expert, Andrew Gimson, in a very fine article for the Mail on Sunday about the Mayor of London’s tussle with the Leader of the Free World. It began with Boris alluding to Barack’s “part-Kenyan” heritage. It finished with Barack chirruping, of Churchill, “I love that guy.” Nothing afterwards – including Boris’s attempt to keep the scrap going – will change the outcome. As Andrew says later on in his article, “this encounter has proved something of a disaster for Boris.”

And others think so too. Elsewhere in the Mail on Sunday, someone from the Leave campaign is quoted as saying, “We had no idea Boris was going to attack Obama so provocatively. It was a misjudgment. He must stop going off-piste.” The trouble for Boris is that he’s representing not just himself but also a cause. If he gets it wrong, the cause can suffer too.

In fact, Boris has had a self-diminishing referendum campaign all round – at least so far. Not long after he announced his support for Brexit, there was that blustering performance on the Marr Show. Then there was that eccentric appearance before the Treasury Select Committee. Then there was that bruising article by Matthew Parris, which exhumed several skeletons from the dirty past. And now there’s this, defeat by Obama. Has Boris ever had a more difficult time in politics?

And yet, and yet… Boris persists. Had all of this been done by a politician with less star wattage – Chris Grayling, say, or even someone who may challenge for the Tory leadership, such as George Osborne – they’d practically be finished by now. But not the MP for Uxbridge and South Ruislip. Even when he’s embroiled in a race row, there always seems to be the get-out that it’s just Boris being Boris. Love him or loathe him, it’s just Boris being Boris. Agree with him or disagree, it’s just Boris being Boris. This latitude, enjoyed by so few other politicians, means that he’ll still be considered a potential future Prime Minister until he either is or categorically isn’t.

Boris’s non-stick powers are nothing new, but time makes them more remarkable. Just when will they diminish? Will they ever diminish? We keep on waiting, and it hasn’t happened yet. For those who want Boris as the next Conservative leader, it must be a joy.

Except sometimes non-stick powers aren’t enough. The trouble for Team Boris is written in recent opinion polls: qualities such as likeability or what-comes-across-as-authenticity aren’t enough for many voters. As Andrew points out in his Mail on Sunday article, “In a recent opinion poll [by ComRes], people said that although they would far rather have a meal with Boris than with Cameron, when it came to looking after their financial affairs, they would trust Cameron more.” The same poll also had Boris trailing Jeremy Corbyn – Jeremy Corbyn! – not just on the question of who should run the country, but also on who would be better at negotiating with terrorists.

And what might worry Boris’s supporters even more is the nature of his recent troubles. Dealing with the President of the United States; appearing before a select committee; making grand statements from Andrew Marr’s sofa – these are all things that we expect a Prime Minister, or a potential Prime Minister, to do comfortably. Like him or loathe him, agree with him or disagree, David Cameron certainly can. Can this would-be successor?