However, William Yeatman, assistant director of the Center for Energy and Environment at the right-leaning Competitive Enterprise Institute, argued that the prospects for environmental petitioners are dim. On its face, "the letter of the law provides for better-than-BART," he said Oct. 25, noting that the courts always accord a lot of deference to the agency on such matters. "Unless they find some smoking gun, I can't imagine them finding better-than-BART [invalid]," he said.

Moreover, he said that the environmental groups' challenge amounts to putting the cart before the horse, given that the D.C. Circuit's decision on CSAPR has been appealed.