There is a very simple reason why it was right for the UK to join our closest allies in launching strikes against the Asad military machine.
This is about our collective future. It is about the kind of world we want our children to grow up in.
It is about – and exclusively about – whether the world should tolerate the repeated use of chemical weapons and the human suffering they cause.
The problem with such weapons is not just that their effect is hideous. Anyone looking at the pictures from Eastern Ghouta can see the kind of suffering involved: the foaming at the mouth, the floppy bodies of children, and the particular terror those weapons deliberately inspire.
Vile, sick, barbaric though it is to use such weapons – that is not the principal objection. These munitions are not just horrible. They are illegal.
It is now centuries since humanity first recoiled against the use of poison in warfare. The French and the Holy Roman Empire were so disgusted by the use of poisoned bullets they signed a treaty to ban them in 1675.
It is now almost 100 years since the great post World War One treaty to prohibit use of chemical weapons – and in that period we have seen nation after nation sign up to the global consensus that this particular means of killing is evil and should be banned.
Indeed, the universal abhorrence of chemical weapons, and the destruction of declared stockpiles, must be considered one of the great achievements of the modern world.
The global community simply cannot afford to turn a blind eye to what is happening in Syria.
In 2013 the Syrian regime committed to destroy its chemical arsenal while Russia – the mentor of the Asad Regime – guaranteed to oversee the process.
Since then the Asad Regime and Russia has made a complete mockery of that pledge.
A significant body of information, including intelligence, suggests the Asad regime was behind the chemical attack at Douma on April 7 that killed about 75 people and resulted in hundreds of casualties.
Multiple accounts located a regime Mi 18 helicopter in the vicinity at the time. The opposition does not have helicopters and no other actor in the Syrian theatre is thought capable of launching a chemical strike of that scale.
The only reasonable conclusion is that the regime has become so hardened and cynical that it is willing to exploit the extra potential of these weapons for removing entrenched urban resistance – in complete defiance of global disapproval and the norms of civilised behaviour.
The Douma atrocity alone would be enough to demand a response. But it is not a one off.
The Douma massacre is now part of a pattern of use of chemical weapons by the Asad Regime. International investigators mandated by the UN Security Council have found the Asad regime responsible for using chemical weapons in 4 separate attacks since 2014.
The UK and our allies have done everything in our power to deter the barbaric use of these weapons. The EU has imposed sanctions on key figures linked to chemical weapons use in Syria.
We have tried countless resolutions at the UN. But Russia has repeatedly shielded the Asad Regime from investigation and censure, vetoing 6 separate UN Security Council resolutions, including torpedoing the UN mandated Investigative Mechanism set up to attribute responsibility for chemical weapons attacks in Syria.
Instead, Russia has repeated its lies and obfuscation that we have seen in this country since the attempted murder of Sergei and Yulia Skripal, including the grotesque assertion that the UK is somehow behind the attack in Douma.
Last year we had a military response from the US, when about 20 Syrian planes were destroyed at the Shayrat airfield after the chemical massacre of civilians at Khan Sheikhoun.
Now the world is forced to act again – not only to protect those who would otherwise fall victim to Asad’s monstrosities, but because unless we do so his regime will continue to weaken what has become an effective global taboo, with significant humanitarian consequences for many more.
If we do nothing there will be other people and other governments around the world who will look at the impunity of Asad and ask themselves: they got away with it – why shouldn’t I?
Unless we act there is a risk of moral contamination, a coarsening and corruption of what we have until now thought to be acceptable.
Yes of course it was also right for the UK to stand shoulder to shoulder with America and France – close allies who were instrumental in helping to forge the 28 strong group of countries that expressed their palpable outrage at the Salisbury attack by expelling more than 150 Russian diplomats.
Yes of course there are diplomatic considerations – but this is about more than diplomacy. It is about principle.
And in its specific focus on the use of chemical weapons – and the consequences that must flow – this action is limited, and we must be both acutely aware of those limits and clear about them.
These carefully targeted and calibrated strikes are not designed to intervene in the Syrian civil war or effect regime change.
The action was carried out to alleviate further humanitarian suffering by degrading the Syrian Regime’s chemical weapons capability and deterring their use.
At a time of understandable tension in our relations with Russia it has been important to stress that this action does not entail some attempt to frustrate Russian strategic objectives in Syria.
In short this does not represent any major escalation of UK or western involvement in Syria – and we should have the courage to be honest about that.
In degrading Asad’s chemical weapons capabilities we intend to do what we can to protect his people from that specific form of cruelty.
We are standing up for principle and for civilised values.
We may not end the barbarism – but we are telling the world that there is one type of barbarism that is banned and that deserves to be banned.