WASHINGTON – The U.S. needs a new, modern arsenal of nuclear weapons to use as a deterrent to attacks from other nations for the remainder of the 21st century, the top military commander for strategic warfare said Tuesday. Air Force Gen. Kevin Chilton, head of the military's Strategic Command, said if the Pentagon develops an improved, more reliable nuclear weapon, the U.S. will be able to reduce the number of warheads it keeps on hand. “So long as there are other countries in the world that possess enough nuclear weapons to destroy the United States of America and our way...