The campaign to keep oil drills out of the Arctic National Wildlife Refuge has just been dealt what could be a fatal blow. Yesterday, Sen. Maria Cantwell (D-Wash.) introduced an amendment to drop refuge-drilling language from a filibuster-proof federal budget bill; today, the Senate voted down that amendment, 48 to 51. "This is too important a question to slide into the budget bill," Cantwell said yesterday. "We are setting a very, very dangerous precedent." But Senate Majority Leader Bill Frist (R-Tenn.) is psyched. "America can't afford $3-a-gallon gasoline and we can't afford to depend on sources hostile to the United States," he said today, though he failed to explain how drilling in the refuge would solve either problem. The Senate budget bill is expected to pass later this week; the House version, which also includes the drilling language, will be voted on as early as next week. The fate of the final compromise budget bill is unclear.