Today’s refugee crisis is one result of doing nothing to stop Bashar al-Assad after he used chemical weapons against Syrian civilians.

Everyone talks about the human consequences of intervention. But we also need to look at the human consequences of doing nothing.

It was a catastrophically wrong decision to fail to intervene two years ago.

The opposite of intervention was never going to be peace. It was always going to be this; children like Aylan Kurdi, dead on a Turkish beach fleeing certain death back home. 8 million Syrian refugees forced to flee their homes.

In 2013, after the first chemical attack, I argued for New Zealand to be part of an international intervention to stop another attack. I said we had a responsibility to protect innocent civilians no matter what country they lived in if tyrants were committing mass murder. Those tyrants must not be able to murder with impunity. If civilised nations did not respond, we were culpable. 

Too many said, “It’s complicated, so we shouldn’t get involved.” They let the tragic mistakes in Iraq paralyse them from supporting the principle that when civilians are under attack we act to protect the innocent.

The 2003 Iraq war was illegal. The weapons of mass destruction didn’t exist any more, as they clearly had in 1988. Syria was different. There was a legal framework under the ‘Responsibility to Protect’ (R2P) principle.

R2P was introduced after the failure of the international community to stop genocide in Rwanda in 1994. 

No one credible doubts Assad ordered the murder of Syrian civilians. We had moral and legal grounds to intervene. 

Those who argued ‘do nothing because it’s too complicated’ need to show us they understand the appalling mistake they made. 

Just as George W Bush is accountable for an act of commission in invading Iraq, there are many culpable for the act of omission in Syria, of failing to intervene when we should have - just as civilised nations failed in Rwanda and in Srebenica. 

You don’t get to oppose intervention on the grounds of humanitarian consequences and then ignore the humanitarian catastrophe of failing to intervene.

We have to do our bit to help mop up now. We have to help the Syrian refuges. One of the main reasons we have to help is that we failed to act earlier. If John Key and National propose a one-off intake of 500 Syrians today, it's a start, but still leaves us behind Australia and other countries who are being more generous. 

And it was a gesture late coming. John Key doesn't like to be unpopular. As was said of a UK politician, you can't replace your moral compass with a clap-o-meter and expect people not to notice.

Be clear what the consequences of inaction are: hundreds of thousands more dead, eight million displaced and homeless, and Assad still killing with impunity.