But the negotiations stalled as the bill moved forward. In Arizona, a right-wing radio host and former congressman, J. D. Hayworth, announced that he was considering challenging McCain in the primary. McCain had never faced a serious primary opponent for his Senate seat, and now he was going to have to defend his position on global warming to hard-core conservative voters. The Republican Party had grown increasingly hostile to the science of global warming and to cap-and-trade, associating the latter with a tax on energy and more government regulation. Sponsoring the bill wasn’t going to help McCain defeat an opponent to his right.
By the end of February, McCain was starting to back away from his commitment to Lieberman. At first, he insisted that he and Lieberman announce a set of climate-change “principles” instead of a bill. Then, three days before a scheduled press conference to announce those principles, the two senators had a heated conversation on the Senate floor. Lieberman turned and walked away. “That’s it,” he told an aide. “He can’t do it this year.”