A Yale Law school alumnus charged by President Barack Obama to promote environmentally friendly “green jobs” resigned this weekend amid what he termed a “vicious smear campaign” against him.

Van Jones LAW ’93, who worked for the White House Council on Environmental Quality, apologized Thursday for making derogatory statements about Republicans and signing a petition questioning whether the Bush administration played a role in the September 11 attacks. But the apology did not stop calls from Republicans for Jones to resign.

“I cannot in good conscience ask my colleagues to expend precious time and energy defending or explaining my past,” he said in a statement, The New York Times reported.