How quickly things change.

This week South Africa allowed Sudan’s president, Omar Hassan al-Bashir, to leave the country while fully aware of the I.C.C. warrant for his arrest on charges of genocide, crimes against humanity and war crimes. The I.C.C. claims to have evidence that Mr. Bashir committed these crimes against the Fur, Masalit and Zaghawa groups in Darfur on the basis of their ethnicity and used the Janjaweed militia to rape and murder civilians.

Mr. Bashir was in the country to attend a summit meeting of the African Union when a small advocacy group called the Southern African Litigation Center, on whose board I once sat, petitioned a court in Pretoria to determine whether it had jurisdiction to act on the I.C.C.’s warrant. The judge ordered the South African government to bar Mr. Bashir from leaving the country.

By allowing Mr. Bashir to leave the following day, while claiming not to know his whereabouts, South Africa violated international law and its own laws too. More important, it sent the message to victims of war crimes throughout the world that they can’t count on the solidarity of South Africa when they need it.

The demise of South Africa’s conscience has not been sudden. For at least a decade, it has sent mixed signals about its commitment to human rights. The Dalai Lama has been refused entry into the country eight times because of the government’s relationship with China, and senior officials have flip-flopped on gay rights at various international meetings despite having one of the only constitutions in the world that includes explicit protections for lesbians, gays, bisexuals and transgender people.

There are legitimate objections to the I.C.C., first and foremost that the court will have little credibility so long as powerful countries like Russia and the United States refuse to subject themselves to its jurisdiction. Many African commentators have insisted that an attempt to arrest Mr. Bashir will lack legitimacy until Tony Blair and George Bush are indicted for their respective roles in the Iraq war. This line of thinking provided the South African government with some political cover for its shameful actions last week, and allowed the ruling party to portray itself as a champion of African autonomy, standing bravely against “the West.”