A few weeks ago I was in Gaziantep, talking to refugees in a camp near the border between Turkey and Syria. There were rows of containers converted into two-room dwellings, there was a school and a clinic - the facilities were basic but sufficient.
But without exception, every single refugee I spoke to was desperate to leave. They were desperate for an end to the chaos, to rebuild their lives and for their children to grow up and live a decent life.
There are millions of people with that plea, both in the countries around Syria and displaced within it. They want us to help bring about peace in Syria.
But compelling though that might sound, that is not the case to go to war.
The justification for airstrikes in Syria is, first and foremost, because Daesh are a threat to our national security.
Daesh and their affiliates have targeted British people: they killed 30 British holiday-makers on a beach in Tunisia and they target young people through social media, inciting them to leave their homes and fight in Syria. And they wouldn’t hesitate to attack us here in the UK, just as they did in Paris, although their plots have been foiled – so far.
At the moment we are targeting Daesh in Iraq, but stopping at the border. This doesn’t make sense. If we are serious about reducing their ability to attack us, we need to degrade their capabilities in their heartland in Syria, not just in Iraq.
It’s also important that we stand by our allies – If we don’t stand with France now, when Paris has been so brutally attacked, when will we?
And what confidence can our allies in the Middle East have in us if we refuse to act now? They face daily threats from terrorist attacks. For many months they have called on us to play a leading role in the coalition against Daesh. We should restore their confidence in us as an ally – and ignore that call no longer.
Of course there are concerns, and MPs are quite right to voice them. Many people fear that this will be another Iraq. I have been reassured that we have learnt lessons from Iraq and that there is a political process happening in parallel with military action.
There is also real commitment to reconstruction: we have committed over £1bn to that effort and will likely contribute more. There is a plan for providing public services as Daesh are overcome, building on the humanitarian work going on in Syria now.
We have to take care that fear about repeating mistakes of the past doesn't confuse our judgement of the present.
Airstrikes will degrade Daesh but not defeat them – some ground troops will be needed. It's imperative one group of terrorists is not just replaced by another.
The coalition – and Britain as part of it – must commit to seeing this through. This action needs to be part of a serious and long-term commitment – not only to Syria, but to the Arab world. This commitment needs to be rooted in a plan.
We should use our influence in the region to promote stability, and we should work with the states that can provide this, recognising that many are fragile and facing continuous existential threats.
As I heard time and again on recent visits to the region, stability in almost any form is better than chaos. And we will need to be pragmatic. Democracies take generations to develop, decades at least, not days.
This action is just one part of the battle we need to wage against Islamic extremism.
We need to degrade Daesh’s military capabilities, but we also need to degrade their communications and their ideological reach. Military action is necessary but not sufficient in itself.
However inaction is also a choice, a choice which itself has consequences. Doing nothing allows Daesh to continue to grow and strengthen. It sends a message to them, and to our allies, that almost nothing will provoke us into action. It reduces our credibility in the political process, for we will have shown we are not committed to the future of Syria. It means we will continue to fight this battle against Daesh half-heartedly.
Daesh hate us; they hate who we are and what we stand for. They want to destroy our way of life and the world as we know it. The battle against Daesh and Islamic extremism is the battle of our generation. Britain, along with our allies, must commit to fighting on all fronts and winning.
Read my speech here