LOS ANGELES - For most of Sam Cohen's life, he has struggled against politicians who, in his opinion, have sacrificed good sense when it comes to the nation's defenses. Cohen is the physicist who invented the neutron bomb, the one that kills people but leaves things like tanks and buildings intact. Plans to deploy his creations in Europe during the '70s and '80s awakened the "peace movement" across that continent, stopping its deployment. With that and other battles lost, the 76-year-old Cohen finds solace in his Brentwood home, nestled high on a hill overlooking Los Angeles. There the world is...