Peacekeeping Works: Evaluating the effectiveness of UN peacekeeping operations

The increase in the deployment of UN ‘blue helmets’ is a key driver of the gradual decline in the number and severity of armed conflicts worldwide since the mid-1990s. We assess the complete, long-term effectiveness of UN peacekeeping operations. It shows a remarkably strong combined effect of UN operations’ ability to contain the lethality of wars as well as preventing them from reerupting or spreading.