Donald Trump prides himself on his ability to make deals. There’s no denying that he has made an awful lot of them. The issue, rather, is that nobody ever actually claimed – or checked – that they were any good.

The latest display of “the art of the deal” represents a new low, even for the White House’s most erratic and self-indulgent occupant in its more than two centuries. Not content with years of indulging Vladimir Putin’s aggression and deceit at every turn, the US President struck a jaw-dropping agreement to lift sanctions on Russian oil and purchase millions of barrels of Russian diesel.

The decision is a direct reversal of a sustained campaign of economic sanctions and restrictions on Russia, intended to limit its ability to raise revenues to fund its war of aggression against Ukraine and its wider campaign of murder and sabotage across the Western world. Those sanctions have been far from perfect – there is widespread evidence of sanctions evasion via relabelled exports through Central Asia, and India is openly buying Russian crude and selling it on after processing – but they are an important tool for imposing at least some financial and political cost on the Kremlin for its actions.

Volodymyr Zelensky was absolutely right in his response to the agreement, which he described as “an investment” in Russia’s war, one that Putin would repay only with “further terror”.

Such an agreement is pure foolishness from a President visibly flailing in the face of soaring diesel prices, driven by his own misadventure in the Gulf. The amounts involved would provide only enough fuel for a few days of domestic consumption, so Trump has sold Western solidarity, the vestiges of American decency and Ukrainian lives for nothing more than a fig leaf for his self-inflicted political troubles.

Even more humiliatingly, it’s clear that Trump fell for Putin’s lies yet again.

The President proudly announced on Sunday that an “energy ceasefire” was part of the agreement, with his Russian counterpart supposedly promising to stop strikes against Ukraine’s energy grid – a tactic that Putin’s forces have pursued relentlessly since the war began.

Mere hours later, drones slammed into Ukrainian gas and other energy facilities, just as they have done for years on end.

Depressingly, this is simply another chapter in the self-beclowning of Donald J Trump.

Literally nobody in the world has any reason to believe that Russia’s dictator is a man of his word; at every stage of his career, he has lied to get what he wants. Small children and uncontacted tribes in the Amazon would pause and think better of shaking hands on any sort of deal with Vladimir Putin.

The leader of the most powerful nation on the planet, with the CIA and humanity’s largest spy satellite network at his personal disposal, has the least excuse of all to be gulled by such a tyrant. Yet he falls for Putin’s lies again and again, whenever they suit his agenda or his self-image.

In this case, Trump has evidently been sold the line that his domestic political problems, looming large ahead of November’s midterms, are down to Ukraine generally and Zelensky personally, conveniently allowing him to disregard his own decision to turn the Strait of Hormuz into a fuel bottleneck blockaded by the Iranian Revolutionary Guard.

It may be shocking, but it is certainly not surprising that he swallowed whole a narrative that placed the blame elsewhere, offered a chance to claim that he was the fireman here to put out his own arson attack, and came at a cost only to the safety and lives of people far away for whom he cares nothing. Perhaps he even fantasised that this – at long last – would give him the Peace Prize that he dreams of hanging on his gaudy Christmas tree.

Now that the deal has turned out to be what the Americans so creatively call a “nothingburger”, Trump is predictably blaming Zelensky, and has reflected not one jot on his own gullibility. He lambasted the Ukrainian leader for his strategy of missile and drone strikes against Russian oil refineries, a bombing campaign that the Ukrainians wryly refer to as “aerial sanctions”.

There is, naturally, no reflection going on in Washington about the fact that these strikes are precisely what has driven Russia to seek the diesel export deal with the US in the first place. Nor is there any acknowledgement that this is a clear sign that the ability to sell oil is, in the Kremlin’s own view, a crucial pillar sustaining the war.

No, instead Trump seeks to rebrand Kyiv’s effectiveness as obstinacy intended to target him personally. Zelensky, he claims, “wants to make problems for the world”, and should be replaced with “a new leader who can make a deal”. It seems he fetishises making deals to the point that he disregards the cost of what is given up and the value of what is received in return.

His timing was even worse than his negotiating skills. Yesterday, Zelensky addressed the Warsaw Security Forum, speaking to an audience of similarly concerned allies who had convened specifically to discuss their support for Ukraine and their fears about further Russian aggression. Poland – Europe’s fast-rising defence leader – France, Germany and Britain all doubled down on their support for the Ukrainians in direct response to Trump’s actions.

Add it to the list of Donald Trump’s many, many deals. It was a dreadful idea to start with, his interlocutor was a liar and a killer who could not be trusted at the best of times, and the grandest achievement it purported to deliver evaporated faster than a Russian refinery on a clear day. If this is the art of the deal, thanks but no thanks.