As South Sudan, the world’s newest country, marks the fifth anniversary of its independence, it faces a deteriorating and urgent humanitarian crisis that is spilling into neighboring Sudan. Reports indicate that hundreds were killed in recent clashes in Juba, the capital, and dozens of bodies were found on the streets of Wau as people fled the northwestern town in search of safety. Even United Nations protection zones have become sites of untold violence. The crisis may soon reach catastrophic levels as rival leaders announced their renewal of the civil war.

South Sudan canceled its July 9 Independence Day celebration because of a lack of funds, but the impending humanitarian emergency is bigger than any lost ceremony. Despite multiple cease-fires since South Sudan’s civil war began in 2013, tens of thousands have been killed, and millions more have been displaced. The daily threat of violence, including against aid workers, is rising.

My research in the region reveals three key trends about South Sudan’s past that help make sense of the current crisis.

1) A long history of war-related human displacement

Migration from South Sudan is reaching a breaking point. Aid agencies in the region are struggling to help those displaced by violence along the oil-rich border between South Sudan and Sudan as well as throughout western Sudan. These organizations are now overwhelmed by 750,000 new refugees fleeing South Sudan. Many of these refugees are returning to Sudan, a country in which South Sudanese people have felt so unwelcome that they voted by a 99 percent margin to secede from it in 2011.

Conflict-related displacement from South Sudan is nothing new. Waves of displacement occurred from the 1950s to 1960s and again from the 1980s to 2000s, during Sudan’s first and second civil wars. Before South Sudan’s secession, Sudan had the largest number of internally displaced persons in the world. Desert tents meant to provide temporary shelter are now re-emerging as lasting fixtures on the Saharan landscape.

2) The importance of religious activism for social change

Religious activism, once used as a rationale to perpetrate violence, can help political leaders in South Sudan make a lasting choice for peace. During the first half of the 20th century, British colonial officials favored northern Sudanese elites in Khartoum, Sudan’s capital, leaving South Sudan to Christian missionaries. But church-related aid groups would later become the lifeline for survivors trapped in war-torn regions after Sudan’s 1956 independence.

Church-affiliated activists also monitored human rights abuses during the civil war that ended in 2005. They clandestinely sent reports overseas to aid groups and the United Nations — often putting themselves at risk of government harassment or detention. As one pastor in Juba told me shortly before South Sudan’s secession, “During the difficult time of war, the church never stopped talking about injustice.”

Today, religious groups in South Sudan continue the struggle to maintain peace among citizens facing the trauma of a repeatedly renewed civil war. As government officials and rival militias resume hostilities, religious leaders advocate for the citizens, delivering public sermons against growing rates of crime and violence, which disproportionately affect the poor.

3) The nascent power of civic groups

My research with civil society organizations in South Sudan reveals that they are working to build the country’s democratic health and rule of law. Even before its secession, South Sudan benefited from multiethnic nonviolent activism by women’s organizations, youth groups, lawyers, doctors, journalists and other professionals. These movements first coalesced in 1964, and in 1985, when their protests took over the streets of Khartoum, successfully replacing military regimes with democratic governments.

In the past decade, hundreds of local and international civic groups have emerged in South Sudan. Today, their efforts to rebuild from the previous war are hampered by nationwide violence and citywide lockdowns. New state universities in the region may also become important sites for youth activists to garner citizen support. After recent student demonstrations in Sudan were met with state violence, nationwide counterprotests ensued to defend the students.

Despite the torrents of hostility unleashed against them, the people of South Sudan share a legacy of struggle and survival. If the region’s history repeats itself, as it has in past iterations of war, the next cycle of violence and rebuilding will involve much needed humanitarian assistance to millions of war-displaced families, as religious and civic groups work to pick up the pieces.

Mark Fathi Massoud is associate professor of politics and legal studies at the University of California, Santa Cruz, and author of “Law’s Fragile State: Colonial, Authoritarian, and Humanitarian Legacies in Sudan” (Cambridge University Press). Follow him on Twitter at @profmassoud.