The only option now open to the west in Syria is whether or not to make it worse. No amount of grandstanding, feelgood rhetoric or intermittent bombing is going to impede the Assad regime’s path to victory in its civil war. It must now be obvious that every ounce of aid given by the west to the Syrian opposition since 2011 has just prolonged that country’s agony. Seven years ago, western intelligence and the western media declared that Bashar al-Assad was about to fall. That was wrong. Since then, half-hearted intervention has been worse than no intervention at all. Outside meddling in the Middle East’s civil wars has never been productive, except of death and destruction.

Assad’s use of toxic gas in rebel-held Douma last week follows ceaseless outside condemnation of previous chemical bomb attacks. When, after their use last year, 59 American missiles rained down on the Syrian airbase of Shayrat, it clearly had zero impact. Regimes fighting for their existence do not care about condemnation or the niceties of international treaties. Nor do their backers, in this case Russia and Iran. They see only a cynical foreign policy coup in the offing.

The 1997 world chemical weapons convention was an advance in defining “acceptable” forms of killing in war. Its defect was that small, poor countries had larger stockpiles. Nor could they see much distinction between their chlorine and sarin and Nato’s horrific cluster bombs and white phosphorous. Photographs of choking children make graphic television, but at least they might survive. We never see the body parts of those blasted to pieces by high-explosive missiles.

Even the Pentagon accepts that it has killed hundreds of civilians in Iraq and Syria

Inhumanity lies in the killing of any civilians in war. There is something peculiarly abhorrent in the targeting of civilian areas of suburban Damascus. But for all its denials the west does it too. Last summer, the monitor Airwars estimated that more than 8,000 civilians died in the fall of Mosul, mostly from inevitably indiscriminate Iraqi, American and British missiles. Even the Pentagon accepts that it has killed hundreds of civilians in Iraq and Syria. As the British commander Maj Gen Rupert Jones says, civilian deaths are “the price you pay” for fighting in cities. Assad would agree.

The laws of war are enveloped in hypocrisy, largely because they are written by the winners. The US has still not signed the convention against delayed-action cluster bombs, one of the most immoral weapons ever devised. They went out of production only last year. Such weapons are still being used by the west’s Saudi allies in Yemen. This whole argument is not over morality, merely degrees of obscenity.

The Syrian war will only end when Assad wins. No amount of armchair ranting will alter that. Then we can all discuss how to condemn him. For the moment, western military intervention is utterly pointless. We must kick the habit of trying to rule the world.