Garvan Walshe is a former National and International Security Policy Adviser to the Conservative Party, and CEO of Brexit Analytica.

What unites far right and far left in 2016? Conspiracy, indifference to the outside world and credulousness towards Russia. They come together in what history will judge the worst sin of omission of the early 21st century, a rival to the Rwandan genocide of 1994: the destruction of Aleppo and the murder of its inhabitants by Russian bombs, Iranian militia and the remaining troops loyal to Assad’s blood-encrusted regime.

In 2013, we could have begun a no-fly-zone that would have tilted the balance of forces towards a negotiated solution. Instead, obsessed with our own psychodrama over Iraq, the House of Commons pretended to itself that doing nothing would keep its hands clean.

In 2015, we could at least have found the means to accept the refugees from the war – Europe could have accommodated a million among its half a billion people – and establish safe havens for others inside Syrian territory. Instead, led by the Poles we left Angela Merkel to cope on her own.

In 2016, we could perhaps have summoned a united international front to attempt serious peace negotiations. But with one American presidential candidate asking “what’s a leppo” and another so pro-Russian that he has invited post-Soviet spooks to hack his opponent’s computer systems, Putin is not irrational to take a gamble on a better deal being available next year. John Kerry’s brief ceasefire never stood a chance.

The West’s loss of confidence is complete. You might think that North America and Europe, together accounting for more than half the world’s wealth, possessor of its most advanced technologies and – however much we might not believe it – political ideals that people in the rest of the world are still willing to risk unarmed death to defend, would be able to summon the resources to deal with a civil war in a country of 21 million.

But we’ve lost the ability to marshal those resources and concentrate them on Syria’s disaster. Our left wing thinks we have through our past sins forfeited the moral authority to use force; while our right would leave Syrians to their fate, and build up fences against them lest they bring its chaos here with them. Their joint fear is of failure. The left think they care too much so do nothing. The right do nothing because they think they don’t have to care enough.

This is a failure of a political generation that can’t get to grips with the advance of globalising technology. As travel and communication get cheaper, multinational business, politics and living get easier. An older generation, that Theresa May spoke for yesterday, find this scary and disorienting. A younger generation, that she spoke against, find it exhilarating and full of opportunity. But nobody has found the ideas, rhetoric or emotional depth to bridge the gap.

Instead, the left globalises the morality of the peaceful, prosperous and democratic world they know – without understanding that their principles can’t just be copied: human rights law developed for societies at peace doesn’t work on the battlefield, while labour regulations appropriate in rich countries turn people out on the streets in poor ones.

Meanwhile the right promises, like the dying society of PD James’s Children of Men, to keep the big bad world out. This isn’t just expensive, though the costs of protectionism are extremely high, but hardens people against desperate suffering in places like Aleppo. The cost isn’t only economic, it’s moral.

Neither is adequate and both lower us in the eyes of the world. That we in the West appear to have followed Bernard Woolley’s advice to appear “heartless and mindless alternately” erodes our standing and deservedly puts Western leadership of the world in question.