South Sudan, the world's youngest nation, marked 15 years of independence on 9 July with no official celebrations and little cause for optimism. A country born in 2011 amid extraordinary popular hope — after decades of armed struggle against Khartoum and a self-determination referendum approved by nearly 99 percent of southern voters — has spent much of its short existence at war with itself. For many South Sudanese, the anniversary is less a milestone than a moment of painful reflection.

The core of the crisis lies in a political rivalry that has defined and destabilised the country since its earliest days. President Salva Kiir, from the Dinka ethnic group, and his former vice-president Riek Machar, from the Nuer community, fought together for independence before turning against each other in 2013, triggering a civil war that lasted five years and killed an estimated 400,000 people. A 2018