BILLINGS, Mont. — Leaders of the Crow Tribe warned Wednesday that a $7 billion coal-to-liquid fuels plant proposed for the Montana reservation could founder unless the federal government throws more support behind the industry. Crow Chairman Cedric Black Eagle said a perceived anti-coal attitude in Washington, D.C., is scaring off potential plant investors. A federal tax credit for coal recently expired. Unless the political climate for coal improves, Black Eagle said, the tribe could be forced to suspend its project, which has been billed as a means to pull the rural reservation out of poverty.