Senate Majority Leader John Thune can afford to lose three Republican senators and still pass the bill, and there are more than that, right now, who have problems with it. Like the House, he will have to balance the concerns from moderate and conservative members of his conference.

Senate Majority Leader John Thune can afford to lose three Republican senators and still pass the bill, and there are more than that, right now, who have problems with it.

Democrats charge that Republicans are acting at the behest of the oil and gas industry and say that California should be able to set its own standards after obtaining waivers from the Environmental P...