Republicans in Congress say a 40-year-old law meant to protect animals and plants from extinction has become bogged down by litigation and is in desperate need of an overhaul.

A group of 13 GOP lawmakers plans to release a report Tuesday detailing their proposed changes to the Endangered Species Act, one of the nation’s cornerstone environmental laws. An advance copy was obtained by The Associated Press.

Proponents credit the act with staving off extinction for hundreds of species — from the bald eagle and American alligator to the gray whale. President Richard Nixon signed it into law in December 1973.

Republicans say only 2 percent of protected species have been declared recovered, despite billions of dollars in federal spending. They want to curtail lawsuits from environmentalists and give states more say over proposed protections.