Ash Carter started his career as a researcher in theoretical physics but quickly became enamored with public policy. As a Massachusetts Institute of Technology scientist, he rose to prominence in 1984 with a report ripping President Reagan’s Star Wars missile-defense initiative as a dud. Recruited by the Clinton administration as a Pentagon assistant secretary in 1993, he helped oversee the removal of nuclear weapons from Ukraine, Kazakhstan and Belarus after the end of the Cold War. During th