President Richard Nixon declared current species conservation efforts to be inadequate and called on the 93rd United States Congress to pass comprehensive endangered species legislation. Congress responded with a completely rewritten law, the Endangered Species Act of 1973 which was signed by Nixon on December 28, 1973 (Pub.L. 93–205). It was written by a team of lawyers and scientists, including the first appointed head of the Council on Environmental Quality (CEQ),an outgrowth of NEPA (The "National Environmental Policy Act of 1969") Dr. Russell E. Train. Dr. Train was assisted by a core group of staffers, including Dr. Earl Baysinger at EPA (currently Assistant Chief, Office of Endangered Species and International. Activities), Dick Gutting (U.S. Commerce Dept. lawyer, currently joined NOAA the previous year (1972), and Dr. Gerard A. "Jerry" Bertrand, a marine biologist (Ph.D, Oregon State University) by training, who had transferred from his post as the Scientific Adviser to the U.S Army Corps of Engineers, office of the Commandant of the Corp. to join the newly formed White House office. The staff, under Dr. Train's leadership, incorporated dozens of new principles and ideas into the landmark legislation; crafting a document that completely changed the direction of environmental conservation in the United States. Dr. Bertrand is credited with writing the most challenged section of the Act, the "takings" clause - Section 2.

Who led the team of lawyers and scientists who crafted the Endangered Species Act of 1973?