Meanwhile, things are heating up on Capitol Hill. At a March 27 subcommittee hearing on EPA's 2015 budget, House Appropriations Committee Chairman Harold Rogers (R-Ky.) declared that if the rule takes effect, it would lead to "the biggest land grab in the history of the world."

He warned McCarthy, "That ain't gonna happen, Madam Administrator. And right here is where a good part of the fight's going to take place, in this subcommittee." She said, "We're not expanding the types of waters that we have traditionally and historically been regulating."

EPA and the Corps also have powerful allies in Congress. Senate Environment and Public Works Committee Chairman Barbara Boxer (D-Calif.) said that, in their proposal, the federal agencies took "important steps to provide certainty and clarity to ensure that our wetlands and streams are protected."

Environmental groups are on the agencies' side, too. Jon Devine, a Natural Resources Defense Council senior attorney, says, "We're girding for a fight, but we know we have the better argument." He says, "We think that better business certainty and cleaner water are a pretty good message to lay out on the Hill, especially when you add in the fact that the expected benefits of the rule will significantly outweigh its costs."

Industry is disappointed that the Supreme Court declined to hear an appeal in the Mingo Logan Coal Co. v. EPA case. That denial let stand a lower-court decision upholding EPA's 2010 withdrawal of two of the three dredge-and-fill permits the Corps issued three years earlier."It's a horrible precedent," says Goldstein. He says industry may have to turn to Congress for help on that issue, too.