South Sudan is in crisis. Since winning independence from Sudan in 2011 after decades of bloodshed, the country has faced a troubled existence. Despite having large oil reserves that could fuel a strong economy, South Sudan remains one of the world’s least developed countries. Its government institutions are dysfunctional. Political and ethnic rivalries between President Salva Kiir and Vice President Riek Machar caused the government to effectively collapse in late 2013, plunging the country into a civil war marked by ethnically targeted attacks.

This conflict has led to a severe humanitarian crisis. Nearly four million South Sudanese, out of a population of about eleven million, have been driven from their homes. As a result, agricultural production and local markets have been disrupted, and food shortages and health needs have grown severe. Over 383,000 people [PDF] have died since the beginning of the conflict.

A UN peacekeeping mission of more than nineteen thousand peacekeepers from more than sixty countries has been present in South Sudan since 2011, seeking to establish peace and ensure access to humanitarian aid. However, this mission so far has been unable to curtail hostilities and has been criticized for failing to protect civilians. The ongoing crisis has also led other countries, including members of the UN Security Council, to consider launching their own humanitarian interventions. Such interventions would be guided by the responsibility to protect (R2P) doctrine, adopted by all member states of the United Nations in 2005 after they failed prevent a number of genocides. According to this doctrine, countries have a responsibility to intervene in other countries when crimes against humanity or genocides are being perpetrated. This norm is not legally binding, however, and its application in past cases has been controversial. Nevertheless, the underlying principles of R2P could serve as a rationale for the United States to take action in South Sudan.