The worst ongoing humanitarian disaster in Africa is arguably Sudan. The basic problem remains in Khartoum, the government lead by indicted war criminal Omar al-Bashir. His regime has killed hundreds of thousands of Sudanese, displaced millions in Darfur and continues war today against many of his people.

The Obama administration came into office threatening tough action against Bashir but not surprisingly resorted to the futile diplomacy of the Bush administration in Darfur. Darfur remains a humanitarian nightmare, and Khartoum has a low-level conflict going with a few other provinces as well as with its former province of South Sudan, although the desperate need of both sides for oil revenues may temporarily limit that conflict.

But there may be a ray of hope for the Sudanese people. The dictatorial Khartoum regime has not quite escaped the Arab spring. The Bashir government is widely despised, and there have been continuing demonstrations against it—in part because the economy is in serious straits. The regime at the top also reportedly is divided, and Bashir’s perch seemingly is in danger. It will not be easy for the demonstrators to succeed, but that should not be taken for granted. A worsening economy will continue to bring them out, to the dismay of Bashir’s colleagues. The Khartoum government is worried.

Neither the United States nor its friends are trying to take advantage of that dissent with concerted efforts to help the opposition. But there is one leader who might make a difference in possibly hastening Bashir’s departure: his good friend, and Turkey’s prime minister, Recep Tayyip Erdogan.

Erdogan has changed Turkey enormously and, although some will dispute it, mostly for the better. But on Sudan, Erdogan’s performance disgraces Turkey and far exceeds U.S. hypocrisy. He has embraced the indicted war criminal, met with him in Turkey and Sudan, and helps keep him afloat by expanding Turkey’s economic efforts in Sudan, which include significant private investment. Visiting Sudan, he declared he never saw any genocide in the country. Even the timorous Turkish press has pointed out the anomaly of his support for Bashir and his zealous promotion of democracy in Syria and the rest of the Arab world.

Erdogan initially fully embraced Assad in his determined initial efforts to help change the Arab world. After the Arab Spring, he quickly pivoted and became the dedicated promoter of democracy and secularism. When Syria erupted, he tried to get Assad to deal peacefully with the opposition but turned against him when Assad resorted to great violence against his people. Since then, Erdogan has been at the forefront of denouncing Assad.

Erdogan has an important public voice in the Arab world and should now put his money where his mouth is—as a professed, dedicated advocate of democracy. He needs to make clear publicly that Sudan’s Bashir is a murderous tyrant and his behavior makes him unfit to rule his country and unworthy of Turkey’s support. It could cost Turkey economically and perhaps lose some political support for Erdogan, but it would be minor. It is time for the Obama administration, which strongly supports Erdogan, to make clear its opposition to his continuing embrace of Bashir. So should the European Union.

It is not clear that if Erdogan disowns Bashir it will get him out or that, were Bashir to pass from the scene, his successor would be any better. But it would be a serious blow to Bashir —and a stance for Turkey fitting with its loudly professed values.

Morton Abramowitz, a senior fellow at The Century Foundation, was American ambassador to Turkey, 1989–1991.