Not long ago, we lived in one of the most peaceful eras in modern history. 2005 saw the fewest recorded deaths in armed conflict since the second world war, according to the Uppsala Conflict Data Program. How times change. Last year, there were 61 “state-based conflicts”, the most since 1946, reports the Peace Research Institute Oslo. Now add the Israel-Iran conflict. Why are there so many wars?

The only thing worse than a biased and brutal police force is no police force at all. The world experienced that shift this century. The 1990s were the heyday of the two global policemen, the US and UN. After Iraq invaded Kuwait in 1990, a UN resolution authorised member states to drive it out. That decade, the American policeman patrolled the world, seeking a near-monopoly of international violence. The “international community” (meaning the US plus friends) tolerated only civil wars in containable arenas: Somalia, Rwanda, Yugoslavia.

Peaceful norms peaked in the late 1990s, when treaties banned landmines and created the International Criminal Court. But then America’s invasion of Iraq in 2003 kneecapped both policemen: the UN, because the US acted without its consent, and, later, the US itself, after that disastrous war created a lasting domestic taboo on sending troops abroad. With China and Russia reasserting themselves, the “international community” dissolved.