It has been a short and turbulent life for South Sudan, a nation born just five years ago. Civil war flared less than two years later, but a power-sharing agreement seemed to heal the rift. That deal collapsed weeks ago and South Sudan is again on the brink of upheaval. Even though United Nations peacekeepers have failed to keep the peace, the U.N. this month voted to boost its peacekeeping presence there, a move that Juba has challenged. The world must bring all its resources to bear to bring peace back to South Sudan.

Conflict has long dominated life among Sudanese. When Sudan was a single country, there were two north-south civil wars: The first lasted from 1955 to 1971, while the second was even longer, extending from 1983 to 2005. Peace negotiations resulted in independence for South Sudan in 2011, but the country descended again into ethnic conflict by 2013, a bloody struggle that resulted in as many as 300,000 deaths, 1 million internally displaced refugees and another 400,000 refugees who fled to neighboring states.

That fight was concluded by an international-brokered August 2015 peace agreement that installed Riek Machar, head of the Nuer, South Sudan's second-largest ethnic group, as first vice president under President Salva Kiir, who belongs to the Dinka, the country's largest ethnic group. Other provisions set aside posts and revenue for each man and his faction, as well as an electoral and constitution-writing process.