The regulations also bar federal agencies from assessing emissions of the gases blamed for global warming on species and habitats, a tactic environmentalists have tried to use to block new coal-fired power plants.
The Supreme Court started monitoring the coal-block-allocation case after Prashant Bhushan, a lawyer and political activist, approached it alleging the government has been interfering in the investigation.
But Republicans still have the power to block climate legislation in the Senate, especially with some Democrats from coal and industrial states also ambivalent about cap-and-trade.