The Return of the Half-Man!
Gil Kane (writer and artist), Archie Goodwin (writer)
First published in His Name Is Savage #1, June 1968 and reprinted by Fantagraphics in 1982 as Gil Kane's Savage #1.
Simon Mace is a retired General that has become a cyborg and he kidnaps the U.S. President. Savage must save the President the only way he can with guts and his .357 magnum.