It's the word 'enforce' that presents us with the tricky bit. Enforcement means action, because unless you actually demonstrate that you really mean it, those minded to break the rules are encouraged to believe that they might well get away with it.
Last night, the Government showed poor judgment in calling a fairly meaningless, and probably unnecessary, vote on potential future action against Syria, a motion which positively invited a 'political' Opposition amendment, and was then lost to a coalition of the Labour Party, government rebels and minor parties.
In doing so, Parliament has effectively, although perhaps accidentally, turned its back on the cause of liberal interventionism in the case of Syria.
Oh yes, we've hardly been consistent in our approach. We only tend to engage with the approval of the US, but someone has to lead, and big countries with sufficient military capacity are required to demonstrate the existence of a big stick.
But, as a liberal, albeit perhaps an old-fashioned one, it's no good talking about the rights of man if, when push comes to shove, you only mean it when it's easy or convenient.
So, perhaps now would be a good time to take stock of our place in the world, and our obligations towards it?