When the archbishop of Canterbury tells you to bomb Syria, you know it’s got a bit serious.

The Church of England has stuck its neck above the parapet to suggest it has seen enough suffering to support the raining down of missiles on the region – all in the name of peace, of course.

Justin Welby insists he and his church’s intervention is motivated purely by the desire to see a safer route for refugees fleeing the country.

Presumably truckloads of refugees in people smuggling convoys could never be mistaken for IS militants from a mile up on those grainy Gameboy-style graphics we always see on the news.

But the stance does represent how far the debate on extending air strikes to Syria has come since it was shoved off the legislative cliff back in 2013.

Of course this time, MPs will vote on whether or not to bomb the other side, in a total about turn over the course of two years where President Assad’s repressive regime is now seen as the best of a bad bunch for the moment.

It is partly the sheer speed of developments in Syria that provides the dilemma for the latest Commons vote – should the rapid u-turn in who we are trying to bomb sound a knee-jerk alarm bell, or intensify the need for action due to how swiftly IS has made its mark?

Either way, David Cameron can’t be as sure of unilateral support as the church, whose vote drew no opposition.

Politicians don’t seem so sure, which is why Mr Cameron laid out his case for the bombing to go ahead. There will always be two camps with this one – though both will admit the future cannot be predicted if the military strikes are rolled out to Syria.

It does seem a little absurd that RAF jets should be permitted to lead bombing sorties over Iraq, but then veer back as soon as they reach the Syrian border.

But the Prime Minister’s case smacks of being a little school playground – ‘we’re one of the bigger boys and can should look after ourselves’ he says, and if everyone else is at it, why don’t we join the gang?

The British attitude towards its place in the world has always had a whiff of egotism, which seems to cloud every decision we take. And while it’s more complex than that, neither of those points seem to me a good enough excuse to make this bombing campaign a formality.

There exists a very real threat, all too cruelly evident in Paris this month, of eye-for-an-eye reprisals on our streets. George Osborne said this week that those risks exist anyway, and have been foiled by MI5 – no doubt they have, but the French security services haven’t exactly been sitting on their hands. And the chilling reality is gunmen in Paris were heard to voice their revenge for this very bombing campaign before opening fire on innocent diners and concert goers. Do we want that here?

Crucially, the Foreign Affairs committee advised the PM there should be no military intervention without a “coherent international strategy” on tackling IS and ending Syria’s civil war.

The only thing that is clear is that there is nothing approaching coherency in the region. Think about it – Russia supports Assad but not the rebels, the US and UK do not support Assad but think he might do ‘for now’, no one knows what sort of government, if any, the Free Syrian Army rebels will go on to form, Turkey shot down a Russian jet and IS rose from the ashes of the last war we waged on the region anyway. Work that one out.

To go full circle in less than 18 months on who to bomb is not coherent, and without and endgame it can be nothing but a gamble.

No one is questioning the evil IS peddles. But who knows what the terrain will be in another 18 months? Apart from a scarred landscape and yet more disaffected Syrians with an even bigger axe to grind.

Of course, inaction is not an option – something needs to be done, be it militarily or politically.

But when you reap what you sow as the West have in recent years, you better hope you plant the right seeds.