On Coffee House today, the Tory MP Johnny Mercer says that Britain lost its ‘strength and leadership’ on 29 August, 2013, the day we decided not to attack Assad. We've heard this line a lot from a certain sort of politician. Michael Gove and Nick Clegg lost their tempers in the hours that followed the Syria vote. Ed Miliband, who turned against the intervention, was called all sorts of horrible names by all sorts of MPs. George Osborne tells audiences in America with his most earnest face on that Britain lost its mojo that day (We got it back, apparently, when we decided in 2015 to bomb Isis – not Assad, but, hey, whatever!)

The let’s-bomb-Syria brigade has never quite recovered from the shock of being rebuffed in Parliament. According to the Mercer, Osborne & co argument, the 2013 vote undermined Britain's status as a force for good in the world. We stood idly by and let evil flourish. We … insert boilerplate sabre-rattling clichés here. And now the Assad and the Russians are gassing and bombing innocents, and using fake news to cover it up, and that is all our fault. Shame on us.

We are so debased, says Mercer, that last year it fell to Donald Trump, of all people, to launch strikes against Assad. ‘How ironic,’ says Mercer, bitterly. And I suppose he’s right: it is ironic that moral leadership in 2016 means being bullied by your daughter to throw a few missiles fairly pointlessly at Assad forces, which appears to be what happened with Trump.

‘We must wake up from our hangover from Iraq before it is terminal for this nation’s global standing,’ says Mercer. The world still looks for us to play a role, he says, but that ‘window is closing’. He’s not quite clear what exactly he is calling for, but I assume he thinks, given the latest disturbing reports from East Ghouta, that military action against Assad and Russia should be on the table, as they say. But it’s almost suspicious that he doesn’t say so outright.

It is also very odd that Mercer doesn’t mention Libya, another disastrous intervention of recent years, one that really should shame our political class but somehow doesn’t. We removed Gaddafi, but then we let the country fall into a terrible mess, and now Libya has slave markets and is a springboard for the refugee crisis. How’s that intervention working out then, Johnny?

Ok, let’s be fair. Mercer is newish in parliament. He didn’t vote for the Libyan war. He also did three tours of Afghanistan. Unlike most war perverts in SW1 – you know who you are – he has had the guts to risk his life for what he believes in. That is admirable. But just because Mercer is a soldier doesn’t mean he is right. In fact -- dare I say it? – his army background might be part of his problem. Military people can often only think of military solutions to diplomatic problems. They can be blind to the broader political consequences of violence. For reference, see the generals now dictating Donald Trump’s foreign policy in Afghanistan. But that’s another row.

Why can’t the Mercers of this world be honest about what happened in 2013. The truth is, David Cameron came back from a holiday and decided in a hurry that we had to take military action. Possibly this was because his wife had just returned from a tour of Syria with Save the Children’s Justin Forsyth (ahem). Cameron then rushed into a proposal to interfere in an extremely complicated conflict, ignoring advice that hurting Assad at that stage would have been a great boon to the various terrorist factions who were fighting the Syrian government. Even hawkish Syrian experts agree that, by 2013, it would have been too late for a western intervention in support of moderate Assad opponents.

Sceptical parliamentarians from different parties rightly asked what the purpose of our intervention would be, what was our strategic objective, what sort of Syria could we realistically expect to create by removing Assad. The government didn’t have very good answers, so the motion was rejected. It was a democratic decision: nothing to be ashamed of.

Before we work ourselves into another frenzy of excitement about the wickedness of Assad and Russia and charge headlong towards a highly asymmetrical war in Syria, perhaps we should do what lots of MPs did in 2013 — pause, reflect on the consequences of military action, and dial down the cant about moral leadership.