South Sudan is less than four years old, but the world's newest nation now tops the ranks of failed states worldwide. After decades of civil war with the north of Sudan, it was meant to be a dream come true.
But the country has disintegrated into chaos. Thousands of people have been killed and almost two million displaced in a civil conflict that erupted in late 2013.
How has a country that was born out of so much promise turned into such a nightmare? Were there warning signs that this could happen?
Fault Lines investigates how a select group of US politicians and advocates shepherded the nation into existence, and asks what responsibility they now bear for the political and humanitarian disaster unfolding in South Sudan.