The term “rules-based international order” wasn’t really used until after the end of the Cold War, but is generally taken to mean the institutions and norms of international behaviour established after the Second World War, particularly as they relate to the United Nations.

It is said to encompass rules that protect sovereignty, preserve peace, curb excessive use of power and enable international trade and investment. Who wouldn’t want some of that? Well, for starters, groups like the BRICS who want to move away from a world dominated by the G7 “global elite” and who question why they should give equal importance to the values underpinning this order - human rights, for example. They’re saying: “That may be your system, but we don’t want to play anymore.”

So with no world government, what power do these “rules” really have, and why should countries pay them any attention?

All valid questions, to which the answer is, well, in an imperfect world and having seen the horror we can inflict on ourselves in the absence of any effort to curb the worst excesses of mankind, we’ve got to try something. Otherwise, and there are some that would welcome it, we’ll be left living in a world described by Thucydides after the siege of Melos in 416 BC during the Peloponnesian War: 

“The strong do what they want and the weak suffer what they must.”

In this episode of Defence in Depth, Dominic Nicholls, The Telegraph’s associate editor, explains how the demise of the post-Second World War settlement may come from within, rather than without.

Watch Dominic’s video analysis above. Find more episodes of Defence in Depth on The Telegraph’s YouTube channel.