Last year, human rights experts warned for many months that a brutal militia was about to overrun a major Sudanese city, El Fasher, and massacre inhabitants.

President Trump and other world leaders mostly shrugged. The militia went ahead and overran El Fasher, slaughtering some 60,000 people in a few weeks.

Now the same militia is besieging another major Sudanese city, El Obeid, which has half a million or more people, and is also threatening populations to the north in the Darfur region. Some inside El Obeid are starving, yet, again, Trump and many other world leaders seem largely indifferent.

Preventing the slaughter would not require military action. It would not even require money. Put aside the arguments over whether humanitarian assistance is worthwhile. (But first, let me say that I believe the billions spent on the Iran war would have been better allocated to $2 bed nets to save children’s lives from malaria.) It may be that all we need to do to avert atrocities in Sudan is to speak up.

The backdrop: Sudan is probably the world’s worst humanitarian crisis right now. The country is caught in a civil war between the army and a largely Arab militia, the Rapid Support Forces, or R.S.F., and while both sides have behaved viciously, the R.S.F. is particularly notorious for savagery, including for killing and raping members of several Black African ethnic groups. While reporting on the Chad-Sudan border in 2024, I interviewed survivors who described the R.S.F.’s systematically killing men and boys over the age of 10 and gang-raping many women and girls.

“We don’t want to see any Black people,” one woman quoted an R.S.F. leader telling villagers before the militia slaughtered the men and boys, among them her five brothers.