The Interior Department on Thursday proposed the most sweeping set of changes in decades to the Endangered Species Act, the law that brought the bald eagle and the Yellowstone grizzly bear back from the edge of extinction but which Republicans say is cumbersome and restricts economic development.

The proposed revisions have far-reaching implications, potentially making it easier for roads, pipelines and other construction projects to gain approvals than under current rules. One change, for instance, would eliminate longstanding language that prohibits considering economic factors when deciding whether or not a species should be protected.

The agency also intends to make it more difficult to shield species like the Atlantic sturgeon that are considered “threatened,” which is the category one level beneath the most serious one, “endangered.”

Battles over endangered species have consumed vast swaths of the West for decades, and confrontations over protections for the spotted owl, the sage grouse and the gray wolf have shaped politics and public debate. While the changes proposed Thursday by the Fish and Wildlife Service and the National Marine Fisheries Service wouldn’t be retroactive, they could set the stage for new clashes over offshore drilling and also could help smooth the path for projects like oil and gas drilling in the Arctic National Wildlife Refuge.