President Trump's pick to lead U.S. EPA, Scott Pruitt, is an avowed foe of the agency's Clean Water Rule.
As Oklahoma attorney general, Pruitt sued the Obama administration over what he deemed an unlawful expansion of federal regulatory power over isolated streams and wetlands. And if he's confirmed as EPA chief, he has said he will replace the rule.
But legal experts say killing that rule is one thing, replacing it another.
Bernadette Rappold, former director of the EPA Office of Civil Enforcement's Special Litigation and Projects Division, said all the legal baggage complicates the effort to write a clear, scientifically defensible rule for protecting areas that are valuable as filters for water pollution, buffers for floodwaters and habitat for wildlife.
"It's not an easy task to begin with, determining federal jurisdiction, and not something most scientists or lawyers know the answer to," said Rappold, who now works for Greenberg Traurig's environmental and litigation practices. "And you're never going to get to write on a clean slate, but this is a pretty well-scribbled-on slate where you have to try to find room in the margins."