We have been here before.  In 2013, sarin was used against civilians in part of the Ghouta suburb of Damascus, as Syria’s civil war raged on.  The western powers unanimously concluded that the Assad regime was responsible.  David Cameron proposed military action in response.  Our view was that this should not be undertaken without a proper strategic plan, and that Britain should avoid being sucked into the war, in which we have no clear national interest, and no strong allied power on the ground.  Cameron’s move was defeated in the Commons.  There was consequently no such action from Britain or other countries.  The Syrian war continued unabated, is now in its seventh year, and Assad is winning it.  Critics of non-intervention argue that the lack of response to Ghouta sent a signal to him and his allies that they can continue to use chemical weapons without fear of reprisal.

Except that he has used them again, there has been a response from the west – and he has now used them yet again.  On April 4 last year, sarin or a variant of it was used in Khan Shaykhun.  Again, the western powers concluded that Assad was responsible.  But this time, Donald Trump replied by launching 59 cruise missiles against a Government base. A United Nations Commission of Inquiry has not confirmed the use of sarin elsewhere in the war since.  But now it appears to have been used again in Douma, another part of Ghouta, and one of the few now controlled by Assad’s enemies.

Once again, the American President is threatening a missile strike.  Once again, our own Government is weighing its options.  Once again, Ministers are glancing nervously across the Atlantic towards the Atlantic at the United States – and even more nervously at the Commons, where there is very unlikely to be a majority for sustained military intervention.  And once again, scores are being settled that run all the way back to the Iraq war.  If you are a committed neo-conservative, Assad’s crossing of an international red line – no use of chemical weapons – is a vivid evidence of why the west must project power abroad in the service of good.  If you are of a more sceptical disposition, Syria’s horrors feature no credible hero and lots of bloody villains.  On the one side is the vile Assad, together with his Iranian and Russian allies.  On the other is an opposition of which fanatical Islamist groups appear to make up a majority.

Through the smoke of claim and counter-claim, and horrible videos of civilian injuries, a few political facts are clear.  The first is that Trump has shown no sign whatsoever of willingness to put American boots on the ground in Syria. Indeed, he has been pushing to withdraw troops in the wake of the folding of ISIS.  The President is notoriously unpredictable, as his North Korean adventure confirms, but he is unlikely to change his position.  One reading of the Douma attack is that Assad knows he is on the verge of victory in Ghouta, and that further American missile strikes are a price worth paying for victory.

As we write, the fog is intensifying again.  Missiles have now hit a Syrian regime airbase.  Responsibility for their use has not been claimed as we publish.  The timing of the Douma incident, a year after the Khan Shaykhun one, is unlikely to be happenstance.  That Assad and his Russian allies are projecting their capabilities, in the wake of the Salisbury attack and the west’s response, may not be a coincidence either.  While we do not dispute that Assad is the villian of the piece in Douma, as elsewhere, we note that some opposition groups have at the least attempted to acquire chemical weapons.  Furthermore, these are far from being the only terror that the Syrian war has produced: consider the use of barrel bombs, dropped by Assad’s forces on civilians.  This site is where we it was five years ago.  The Commons will be the arbiter of any proposed military response to Douma.  It should proceed very carefully indeed.