Theodore Roosevelt (2015). “Theodore Roosevelt on Bravery: Lessons from the Most Courageous Leader of the Twentieth Century”, p.39, Skyhorse Publishing, Inc.
Third Annual Message to Congress, 7 Dec. 1903. "No one is above the law" appears in the U.S. Supreme Court case Mississippi v. Johnson (1867) (arguments of counsel). Even earlier, "no officer ... is above the law" is found in a Kentucky Supreme Court case, Johnston v. Commonwealth (1809).