In a world where blowing up a factory seems to be the only anti-poverty measure Western governments won’t spare any expense for, the worst thing you’re likely to hear about the United Nations’ blue helmet–clad peacekeepers is that they’re ineffective. Like the UN itself or the idea of international law, its peacekeepers are generally viewed as a force that would be mostly unobjectionable if it only worked or was — snicker — actually taken seriously.

This simple story masks two crucial facts. One is that, far from a ramshackle fighting force, UN peacekeepers have had some genuine successes in their seventy-year history. The other is that the nature of UN peacekeeping has drastically, and alarmingly, changed in the last few decades.

Technically, there’s no basis for peacekeeping in the UN Charter. The doctrine was developed largely by the organization’s second secretary-general, Dag Hammarskjöld, as well as institutions like the International Court of Justice.