Tim Farron's opinion on the Syrian Airstrikes ahead of the debate in Parliament.
The decision every politician dreads is whether or not to send brave servicemen and women into military action in defence of our country.
When the Government asked MPs to support extending airstrikes into Syria in 2013 to target Assad, I refused to provide that support. I was not convinced at that time our intervention was properly effective, nor that it would be backed by a diplomatic effort to establish a lasting peace or prevent more suffering than it caused.
In response to that deep-rooted scepticism last time, I wrote to the Prime Minister last week together with Nick Clegg, Paddy Ashdown, Ming Campbell, Kirsty Williams and Willie Rennie setting out five principles against which the Liberal Democrats believe the case for extension of military action against ISIL in Syria should be based.
It is my judgement that, on balance, the five tests I set out have been met as best they can. I will therefore be asking my parliamentary colleagues to join me in the lobby to support this motion.
I have written in more length about how I have reached my decision. I hope you will take the time to read it here.
I believe it is right to support what is a measured, legal and broad-based international effort to tackle the evil regime that has contributed to the hundreds of thousands of desperate refugees, fleeing for their lives.
As a Liberal Democrat I am an internationalist. I believe in acting collectively with our friends and our European allies, joining Germany, France, Denmark, the Netherlands and others in responding to threats to our security within a framework of international law.
I was a proud supporter of Charles Kennedy when he led his MPs into the lobbies against an illegal war in Iraq on the basis of a dossier that sought to contrive a threat where none existed. This war has cast a long shadow over Britain's role in the world and has severely damaged the confidence that the British people have in our intelligence services and the decisions of our Prime Ministers.
But this is not Iraq.
The Liberal Democrats were also the first party to call for action in Bosnia and Kosovo led by Paddy Ashdown. We call for action again now. The threat to Britain and our allies is clear. We can and must play a part to extinguish ISIL.
I am well aware that many in the party will disagree with me. I hope that, even if you cannot support me, you can support the approach I have taken and recognise that I have taken this difficult decision after the fullest consideration.