According to a recent column, the military has estimated that only about 20 percent of the draft-age population is physically and mentally able to serve in the military.
People get bumped for all kinds of things. One of my teachers, who is healthy and in his sixties, got bumped for having poor circulation. A military doctor took one look at his feet and said “forget it.” There’s no arguing the point—it just happens.
Lots of people who got rejected for health reasons went on to lead normal lives. Howard Dean had his back injury and went skiing. Jack Kemp had bad knees and went on to play football. As one military expert said (approximately) “you can always stop the football game if someone’s knees buckle. But you can’t stop a battle for that reason.”
Joe Namath had bad knees and was rejected by the Army to serve a consolation career in football. Cassius Clay became Muhummad Ali and was suddenly a CO, free to pursue a career in non-violent boxing. John Kerry joined the Navy and after four months in Vietnam endangering his shipmates he was sent packing.