Anyone who has been lucky enough to gaze up at the sky and spot a bald eagle soaring high above has benefitted from it.

The “it” we’re referring to is the Endangered Species Act, which became law of the land (and the skies) 50 years ago last week, when President Richard Nixon unceremoniously signed it on Dec. 28, 1973.

Nixon was under fire from the ongoing Watergate investigation that would eventually take down his administration, signing the bill with little fanfare at his “Western White House” in San Clemente, Calif.

“At a time when Americans are more concerned than ever with conserving our natural resources, this legislation provides the federal government with needed authority to protect an irreplaceable part of our national heritage—threatened wildlife,” Nixon wrote in a short statement that accompanied the signing.

“This important measure grants the government both the authority to make early identification of endangered species and the means to act quickly and thoro...