Our cover this week considers Sudan’s catastrophic war. It has received a fraction of the attention given to Gaza and Ukraine. Yet it threatens to be deadlier than either conflict. More than 10m people have been forced to flee their homes; some estimate that 2.5m civilians could die by the end of the year because of famine. No one can easily put Africa’s third-largest country back together again. But it is possible to save millions of lives, and reduce the chance of calamitous geopolitical aftershocks, if the world acts now.