Theresa May is right not to join the US and France in going to war with Syria

Unpredictable events in the next few days may change everything, but at this distance it looks very unlikely that the British will be joining in the Franco-American front against Syria and its Russian allies. If so, then that is for the good.

The most immediate reason is quite simply that Theresa May lacks the backing she would need in the House of Commons to support such a serious move. There may be circumstances in which parliament’s will can be assumed or bypassed, and British military action taken through the traditional method of the royal prerogative – say in retaliation for a nuclear strike. Legally, strictly interpreted, that option remains open to the government in any event.

Politically, however, and as an elective act of deployment of British firepower, air strikes on Syria, including possible collateral damage to Iranian and Russian personnel and materiel, would have to be sanctioned in advance by the Commons. The precedent Tony Blair was pressured into setting at the time of the Iraq invasion in 2003 was a powerful one (though events prove that MPs got it wrong).

At the moment, too many Tory backbenchers are expressing disquiet about the escalation of hostilities with Russia for Ms May to be confident of carrying the house without the support of the main opposition parties, and neither Labour nor the SNP seem likely to help her out. At best, Ms May would receive a shaky mandate; at worst she would suffer the same humiliation that David Cameron did when he sought permission for much the same action in 2013. Unlike her predecessor, she is not in a strong enough position to be able to survive such a setback unscathed.

So many of the arguments about whether Britain should take part are overshadowed by the probability that it won’t because the political willpower is not there. What seems to have focused many minds is the promise of the Russian ambassador to Lebanon that Russia would attack the “source” of any missiles aimed at Syria and its backers, meaning that ships, submarines or land bases could be vulnerable to a swift Russian reprisal. After that? The scenario is too horrible to contemplate, and certainly too grim for many Conservative and Labour MPs to entertain.

All of which leaves the Syrian people in the same beleaguered position they were in, and, still more depressingly, an increased risk that chemical weapons will come to be used more frequently, if not routinely. The taboo against these particular weapons of mass destruction, which uniquely terrify mankind, will soon be ended. It is a grim moment.

It is also a time to reflect on the usefulness of the British nuclear deterrent. For the theory of nuclear deterrence requires that both sides believe the other will use them, and this constrains them from making threats and engaging in dangerous brinkmanship. We have long accepted that in “small” wars, such as the Falklands and the conflicts in Iraq and Afghanistan, they were not relevant. Yet the British stuck to the view that the nuclear deterrent would work against a power such as Russia: our nuclear weaponry would prevent the Russians from bullying us and would make them think carefully about acts of aggression. Now, after the Skripal affair and our apparent powerlessness in the light of events in Douma, nuclear weapons of mass destruction look simply irrelevant.

It is right that parliament should weigh all of these considerations; such is their gravity for national security and the lives of British citizens and those of other nations. It would be intolerable if another failed intervention – echoing those in Iraq, Afghanistan and Libya – were to take place against the wishes of the representatives of the people. If it means the American and the French presidents going ahead on their own, then so be it. They will need to be answerable for their actions to their people, and it is not entirely clear where they think the escalation will end. Surely, now is the moment to pause.