Theresa May’s inclination will be to participate in American-led action against Bashar al-Assad’s regime.  It would be surprising were it not.  She will feel that the use of chemical weapons endagers the international order, and that the western powers cannot let it go without retaliatory action.  This sense will be heightened after their use in Salisbury.  America and France supported her call for a united front against Vladimir Putin then.  She will want to support both in their planned action against Assad now – whatever Russia may say.

Furthermore, there will be a sense in parts of the Foreign Office, Whitehall, and her own party that we cannot fall behind our western allies as they march on, let alone stand still.  The logic of the Government’s post-referendum, pre-Brexit policy is that the country will be a Global Britain, no less engaged with the world as an independent country than it was as an EU member.  Inaction over Syria would isolate us from our main allies abroad.  It would leave Emmanuel Macron and France as Europe’s main military actor.  It would do us no favours with a volatile American President from whom we hope for support for a free trade deal.  It could conceivably have a knock-on in the Brexit negotiations.  There may also be a belief in some Tory quarters that strikes against Assad would further highlight Jeremy Corbyn’s habit of appeasing Putin, so unmissably shown up after the Salisbury assault.

Now consider the other side of this coin.  It is reported today that the Prime Minister is inclined to order some military engagement without first calling a Commons vote.  She has every right to do so and we agree with James Gray and others that this is the correct constitutional practice: the executive should act and the legislature hold it to account for its actions.  But it is far from clear what this engagement and its timetable might be.  May will presumably be wary of Typhoon fighters or Tornados being shot down over Syria.  However, it isn’t clear how long it would take to deploy cruise missile-armed submarines to the region, or how the timetable of their deployment might dovetail with the return of the Commons next Monday.

The political difficulties are more knotty than the practical ones.  Parts of Whitehall may want the Government to fall in behind America, but much of Parliament will not.  Thirty Conservative MPs voted against military action in Syria in 2013.  They included four present Ministers – Steve Baker, Tracey Crouch, Phillip Lee and one Cabinet member, David Davis.  Their reservations about David Cameron’s intentions were shared more widely.  Our judgement is that there will be more Julian Lewis’s on the Tory backbenches (the Chairman of the Defence Select Committee, and opposed to strikes) than Tom Tugendhats (the Chairman of the Foreign Affairs Select Committee, and in favour of them).  Ominously, ConservativeHome is told that the whips have not yet done a ring-round.  They and other MPs are away from Westminster during this parliamentary recess, just as was the case in 2013.

Today’s Times says that polling finds that a fifth of voters in favour of missile strikes, with two fifths against and the rest undecided.  The legacy of Iraq is long.  Trust in Ministerial and security services assurances about intelligence has been eroded.  Social media allows conspiracy theories to get halfway round the world before government dossiers have got their boots on – and been denounced as dodgy.  Public support for a clash with Russia over Syria will doubtless be lower than a fifth.  Corbyn’s take on Russia is one thing when poisonings are taking place on British soil, but likely to be another if our armed forces go into action over the skies of Mesopotamia.  He would proclaim that he had been proved right about Iraq.  That view would find support among people more reputable than Nick Griffin.

The Labour leader will be able next week to denounce Trump’s characteristic tweet yesterday as warmongering.  (“Russia vows to shoot down any and all missiles fired at Syria. Get ready Russia, because they will be coming, nice and new and “smart!”)  The Prime Minister will be asking herself what echo his words might have in marginal seats and among nervous Tory backbenches.  She will want to be sure that any action she authorises isn’t followed by ministerial resignations.  Her leadership is not currently under internal threat, but her position is far from secure, in this Commons with no majority.  No wonder she has called an emergency Cabinet meeting this afternoon.  She wants to test the waters, bind its members in.  Boris Johnson and Michael Gove will be for action.  The Defence Secretary is a neophyte facing his first big test in office.  Davis is unlikely to have shifted his view much since 2013.  Most Cabinet Ministers will feel the competing pulls of wanting to support May but also distance themselves from potential political damage.

The Prime Minister will need to convince her colleagues that intelligence demonstrates Assad’s culpability beyond doubt.  The questions that will follow from her colleagues will include those that this site asked yesterday.  If there are further chemical attacks in Syria post-missile strikes, what would Britain do then?  What is our strategic interest there, in any event?  Where do we stand between “monsters and maniacs”, as Lewis has put it – between Assad and his Russian and Iranian allies, and Al Qaeda-aligned Islamists?  Is there really a credible democratic alternative?

What response might Putin make?  What is his capacity for cyber response or an asymetric riposte – in the Ukraine, the Baltic States?  What is the danger to British personnel, and of the situation spiralling out of control?  The potential interplay between an unpredictable American President; a belligerent but vulnerable Russia; a broken UN system; an appeasing Leader of the Opposition, a windy Commons and a weak Government is baleful for May.  Her best option is a strictly limited missile response – no warplanes over Syria, let alone boots on the ground.  She will be feeling a hand of history on her shoulder, and wondering if the other holds a knife at her back.