Air America, the stupefyingly dull liberal radio station headed by Al Franken, is in full Chernobyl mode. (Hat tip: zombie.)

The chairman and vice chairman of Air America Radio have resigned, dealing the latest setback to the fledgling liberal radio network headlined by comedian and author Al Franken.

The departures of Evan Cohen and his investment partner Rex Sorensen came just a week after the company said co-founder Mark Walsh had stepped down as CEO to take a smaller role at the company. The company also said last week it had forced out David Logan as head of programming.

Cohen declined to discuss the reasons for his departure Friday but confirmed he was stepping down as chairman and as a member of the company’s board. News of the departures, which occurred Thursday, was first reported in the Chicago Tribune.

Cohen also said Sorensen was leaving the board. He declined to say what he and Sorensen planned to do with their stakes in the venture. Jon Sinton, president of the company, did not return calls seeking comment.