Mainly due to the abject wickedness of homo-sapiens there needs to be systems of government that limit power. These systems have to ensure that no one individual or particular group is able to gain disproportionate leverage on control. This limitation of power is what lies at the heart of liberal democracy. It’s a relatively recent feature in history and is the sine-qua-non of modern politics, the development without which it would be impossible, given the way humans are, for societies to flourish.

Philosophically, it can be understood as a negativist idea in contending that humans are not able to handle power very well without damaging others and ultimately themselves and so they need to be restricted in their capacities. It is now widely held that political systems recognise this need for limitation. So, in a modern government the executive is separate from the legislative which is again separate from the judicial. Religion is kept away from the State. Leaders get only so long and are then removed to be replaced by different ones.

Another example of negativist political philosophy is freedom understood as absence of coercion. Isaiah Berlin called it negative liberty. It says: you can do as you like as long as it doesn’t interfere with someone else. If it does there is a procedure for resolving the dispute. That procedure is the legal system with its attempt at impartiality and justice. Its rulings are able to be enforced by coercion if necessary.

I think that a serious question for the future of international politics is this: that in the interests of building a world where the principle of limitation is upheld by every nation state both inside and outside national boundaries, do we coerce those states who do not recognise the benefits of the liberal system into conformity? Coercion itself is not favoured by liberalism and so in theory it violates one of its central tenets. However, it's not that liberal societies aren't coercive if and when they have to be. It's that they always prefer not to be unless absolutely necessary.