We know how this ends. Even if the circumstances do not permit much on the ground reporting, messages from doctors and civilians revealing the horrors of the final assault by the Russian-backed Syrian regime are making it out of Aleppo. We know how this ends too, unfortunately, because of the work of historians who have written detailed accounts of the culmination of the fight for Stalingrad, of the travails of Warsaw and of Berlin’s fall. War of that level of intensity dulls and then obliterates the senses, until soldiers who would never consider behaving like animals in peacetime perpetrate horrors beyond imagining on the enemy they capture and on civilians unlucky enough to be caught in the middle.

That is happening right now, in Aleppo. And it is happening ‎as a direct consequence of the abject failure of Barack Obama’s foreign policy.

That failure is sometimes overlooked because all the focus of late has been on the anticipated failure of the policy of the next President, Donald Trump. But Obama deserves a large share of the blame for the Aleppo disaster, because it is the end result of his approach to dealing with the Middle East and with Russia.

When he came to office, the Obama doctrine, you will remember,‎ was termed “leading from behind” which meant not leading at all, or leading only a little in an unhurried take-a-chill-pill posture. It sounded kinda cool at the time, after the meltdown of Iraq, when foreign entanglements were out of fashion. America was going to stop hanging tough and start hanging back. This had its attractions, even for weary neo-cons. As Christopher Hitchens put it at the time, Obama was a “cool cat” and we felt we needed a little of that after the intensity of the Bush years. But Obama was too cool for our own good, it turned out.

For those of us who had hoped briefly and naively in 2008 that he might turn into a Truman figure – or discover in office that if America doesn’t lead then someone else will – the tragic trajectory of his presidency has provided a bitter lesson in the limits of presidential charisma.

The weakness of Obama is actually best illustrated with reference to what happened in Britain, in relation to Syria. In August 2013, David Cameron, then Prime Minister, sought parliamentary approval for action. The vote was lost in the Commons when Ed Miliband, then Labour leader, led the opposition and 30 Tory MPs and nine Lib Dem MPs rebelled. On the night it seemed like the most shocking repudiation of Prime Ministerial authority, although Cameron’s calm acceptance of the vote meant the coalition government was barely dented.

Where the impact was biggest was in Washington, where President Obama took it as a cue to offer Congress an effective veto, although no vote was needed. The result was the scrapping of US plans for greater involvement aimed at preventing the Syrian regime using chemical weapons. The Russians, and their allies the Syrians, saw their opportunity in this weakness. America was not going to get involved – other than trying doomed peace initiatives and some later air strikes – and Russia and Assad had the field of battle against the rebels to themselves. That leads to the horrors of Aleppo today.

But consider the strangeness of what happened. Obama and his approach had been the norm for a while, meaning his backing down because of a rebellion led by Ed Miliband was generally taken as just the way things must be. Does that compute? The President of the United States backed off in Syria because of the machinations of Ed Miliband and the decision by the depleted Brits to not take part?

Even Miliband was taken aback when Obama took it is a signal to do almost nothing, assuming as Miliband and others did that the vote in the Commons would merely be a precursor to a discussion about a better planned international effort to halt the conflict. No, Obama was looking for an excuse to not get involved, with the results we see – or don’t, but can imagine from the historical record only too well – in Aleppo and in the migration crisis.

There are no easy answers is the foreign policy equivalent of “it’s a game of two halves” or “the nights are fair drawing in,” but this is the stuff a good American leader gets paid to deal with. Short of a full invasion, or providing a large number of troops, there is plenty an engaged US could have done in Syria in the last three years. Obama chose not to try.

Weakness is only part of the explanation for inaction. Another part of the answer to why Obama behaved like this in office lies, I suspect, in his bookish self-absorption and obsession with being seen to be a great thinker incapable of rashness or excessive emotion. That routine reached almost comical proportions in the latest extremely long and tiresome interview with Obama in the New Yorker recently. The editor of that magazine is David Remnick, a chronicler or even disciple of Obama. The Obama on show in the latest Remnick profile is beyond parody.

Obama is obviously in love with being Obama, seeing all the angles, stroking his chin, offering homilies and street-smart theories, like a writer for the New Yorker that reveres him, or a liberal American academic musing away over dinner in Georgetown. Look, I like academics, a lot. They’re often terrific types. But it turns out it is not a good idea to make an academic the President of the United States, especially not if he has go up against Putin and Syrian despots armed with chemical weapons. We know how this ends.