The latest airstrikes in Syria were a cautious gesture of disapproval rather than a dent in Assad's military machine

In the event, the fears of a Russian-American clash and runaway confrontation leading to a third world war have turned out to be overblown

“Big noise on the stairs, but nobody comes into the room,” runs an old Chinese saying. This is an apt description of the very limited airstrikes on Syria launched by the US, Britain and France overnight, which came after apocalyptic tweets from President Trump and threats of military retaliation by Russian diplomats.

In the event, the fears of a “Russian-American clash” and runaway confrontation leading to a “third world war” have turned out to be overblown. They did not look quite so exaggerated earlier in the week when Trump tweeted about US missiles: “Get ready Russia, because they will be coming, nice and new and ‘smart'.”

The Russians hinted that their retaliation might include American targets.

Of all the options available, the US-led coalition chose the one involving minimal action and geared not to provoke Russia or Iran. This was a one-off attack on three suspected Syrian chemical weapons facilities, one in Damascus and two west of Homs. It was more of a gesture of disapproval than an attempt to damage President Bashar al-Assad’s military machine. Hours after the missiles had struck, his supporters were understandably demonstrating their defiance in the centre of Damascus.

Trump, reportedly under pressure from his military chiefs, may have chosen the most cautious option, but in fact there were no good options. Assad has all but won the civil war. Even if it was possible to weaken him, this might present opportunities to Isis and al-Qaeda, which are battered but not entirely out of business.

The attacks may or may not deter Assad from using poison gas in future, but they will not change the balance of power against him. Chemical weapons are only a small part of his arsenal and have played only a minor military role in the war. Out of the half million Syrians who have died in the conflict over the last seven years, just 1,900 are estimated to have been killed by chemical weapons.

Yet the military balance of power really has changed in Syria over the last week, although the reason for this has largely passed unnoticed internationally because of the focus on the gas attack in Douma and its consequences. The big development is that Douma, the last armed opposition stronghold in Eastern Ghouta, surrendered to the Syrian armed forces on 8 April. The remaining Jaysh al-Islam fighters have been taken by bus to Turkish-held territory in northern Syria during the course of the week. This is Assad’s greatest victory of the war, surpassing in importance even the recapture of East Aleppo at the end of 2016.

The Syrian army began its so-called Rif Dimashq offensive against the towns and villages of Eastern Ghouta on 20 February. For seven years, the survival of this opposition enclave in east Damascus had been a sign that Assad did not control all of his own country. There were rebels within mortar range of the heart of his own capital who regularly bombarded the Old City. In the past there were other such opposition enclaves, but they have fallen one by one.

Eastern Ghouta had a population of 400,000 and was partly agricultural so could feed itself to some degree. It was at first blockaded rather than besieged, with supplies coming in through a vast tunnel network and permissive or corrupt government checkpoints.

But in the last year the government has closed entry and exit through its checkpoints and has blocked the tunnels. Inhabitants started to suffer from an acute shortage of food, fuel and medical supplies. The scarcity got worse when the government began its offensive in February. Much of the population took refuge in basements where they could only see in the dark by using small torches. Those who lived there complained of the lack of fresh water and food, the stench because of broken sewage pipes and the presence of venomous scorpions.

Possibly it was the Syrian government's frustration at the continued resistance of part of Jaysh al-Islam, the Saudi-backed jihadi movement in Douma, that led it to use chlorine gas. It had done so before without provoking an international reaction, but this time authentic-looking video was broadcast around the world showing dying children gasping for breath. The pictures provoked a wave of international fury which culminated in the US-led airstrikes on 14 April.

If the Syrian government’s purpose in launching a chemical weapons attack was to force the final surrender of the Douma rebels, then it succeeded. Within hours of it happening, Russian military police moved into Douma to supervise the departure of rebel fighters and to suppress looting by government forces. On 12 April, the Syrian national flag was finally raised over a building in central Douma and the long siege was over.