Joe Biden mangled an effective message when he called for Vladimir Putin to go

Vladimir Putin is a “butcher”, declared Joe Biden after he met Ukrainian refugees in Poland. This is no more than a factual description of a brutal leader for whom life is cheap. Unfortunately, the US president went beyond mere facts in the last line of his speech in Poland, when he declared: “For God’s sake, this man cannot remain in power.”

It is an admirable sentiment, but it was a mistake for Mr Biden to express it. It looked as if he were setting out US policy, which was why White House officials immediately “clarified” that the president had not meant what he said: “The president’s point was that Putin cannot be allowed to exercise power over his neighbors or the region. He was not discussing Putin’s power in Russia or regime change.”

They know, even if Mr Biden briefly forgot, that Mr Putin is desperate for his fight to be with the US. The Russian president’s worldview seems to be based on a mythical history of the Greater Russian people, who include Ukrainians and other Eurasians, in a struggle of civilisations against the decadent west, led by a morally compromised America. He thought he had taken up arms against a “Nazi”, westernised elite that is oppressing the Ukrainian people, only to discover that the Ukrainians do not want to be part of his empire.

Mr Putin wants to portray the war as being between Russia and the US-led Nato alliance because the alternative is to accept that it is a war of aggression waged by the Russian military state against its Slav neighbours and cousins.

That is why it matters that President Biden, whose tour of Europe had otherwise been a success, allowed himself to be hooked into Mr Putin’s framing of his war as a conflict with the US by proxy.

Until now, the US president has avoided this trap. He drew the line at enforcing a no-fly zone over Ukraine, and at supplying Polish MiG-29 fighter jets. This attracted some criticism at home, from an American public who think he is not being “tough enough” on Mr Putin. Mr Biden may know better than the American public that they do not want to be drawn into a nuclear confrontation with the Russian military.

It seemed that President Biden had a better idea. Do not do what your opponent wants you to do. Supply the Ukrainians with the less visible equipment they need. The Ukrainians so far have been effective in enforcing a no-fly zone themselves, using western-supplied missiles.

And tell it like it is: Putin is a butcher. That is not what the Russian people want. And if it doesn’t deliver what they do want, which is mostly material comfort and security, as it is for most people around the world, they will not tolerate him for long. No amount of mystical goo about Greater Russia will make up for a failure to deliver bread, peace and land.

President Biden has interrupted Mr Putin’s mistake with a mistake of his own. He needs to correct it and, in concert with all friends of the Ukrainian people, he needs to persevere with the strategy, which is to tell the truth about Putin and pass the ammunition.