In 1905 he was a member of the City Party, a reform group that challenged the Republican political machine in Philadelphia. At the request of Henry Stimson, Pepper agreed to represent Gifford Pinchot whose charges of undue favoritism against Taft's Secretary of the interior, Ballinger, had led to a scandal, the Pinchot–Ballinger controversy, as well as congressional hearings. Despite his admiration for Roosevelt, Pepper supported Taft in 1912, but rebuffed an offer of a judgeship on the United States Circuit Court of Appeals as well as refused to respond to movements that attempted to draft him for mayor of Philadelphia. His involvement in national and international church affairs, discussed above, also prompted his increased political activism.