Sudan: 'Is U.S. Without Leverage in Confronting Khartoum Over Atrocity Crimes?'

The Obama administration would have us believe, in the words of special presidential envoy Princeton Lyman, that we can do nothing but "encourage talks" between the increasingly militarized Khartoum regime and its countrywide adversaries. Privately, Lyman says the U.S. has no leverage, "no cards to play," no effective way of pressuring Khartoum. Is this true?