“THE only thing necessary for evil to triumph is for good men to do nothing.” Burke was writing 250 years ago, but his wisdom applies just as much to Syria.

Chemical weapons are the most despicable of all, and have for decades been outlawed throughout the world. Yet they have been used often by the dictator Assad in Syria, at least partly no doubt encouraged by our failure to act in 2013.

Closer to home, a similar agent was used in a failed murder attempt on the streets of Salisbury. Next time it could be a mass gas attack in the London Underground. Use (or possession) of these weapons cannot be allowed, and Theresa May was wholly justified in her surgical strike against chemical weapon factories and stockpiles in Syria last weekend.

The PM stood up well to the fuss which the pacifist Leader of the Labour Party tried to make in the Commons on Monday, straightforwardly laying out the reasons and the outline legal justification for the strikes.

It was quite right that she refused to expose the secret intelligence, or indeed the detailed legal advice over targeting, which she had shared with the Cabinet before the strikes. Those are matters for her, and for the generals and intelligence chiefs who advise her. It is on the basis of that advice that she herself took personal responsibility for ordering the military action, rather than seeking ‘political top-cover’ by asking for a vote in the House of Commons.

It is the PM’s heavy duty to decide on these matters; and it is the responsibility of the House of Commons to hold her to account for it, as we did in the very full Parliamentary debate on Monday. The separation of responsibilities, between Executive and Legislature, is vitally important to the proper conduct of warfare.

Our ability to scrutinise what the PM has decided was badly undermined by Tony Blair’s insistence on a vote to cover up his illegal invasion of Iraq in 2003. By getting his backbenchers to be whipped into supporting him, Blair was abdicating his responsibility for that terrible decision. 2003 also amply demonstrates that a vote in the House by no means necessarily results in the right decision being taken.

So I strongly support the PM’s action in striking against the chemical weapons capability of Assad. She was not taking sides in the civil war; nor was she seeking to topple the dictator (even although some people would like her to have done so). She straightforwardly struck against the sites where these appalling weapons are made and stored. She was wholly justified under international law in doing so.

And she reasserted the constitutional right, and the strategic and tactical necessity, of the Government taking responsibility for warfare; the Commons thereby strengthening their duty and their ability to scrutinise what the Government have done and truly to hold them to account for it.