U.N. peacekeeping really can be effective. Here’s how we tabulated this

Syria’s seven years of conflict have had devastating consequences, with hundreds of thousands of people dead and more than 4 million refugees. Would the story be different if the United Nations Security Council had managed to come to an agreement and deployed a peacekeeping operation (PKO) early in the conflict? Would a PKO have been able to resolve this conflict? Despite popular conceptions to the contrary (see also here and here), a large body of research has shown that PKOs are surprisingly effective at keeping the peace.