Since 911, there has been an outgrowth of terrorist activities both abroad and here at home. Let's consider a short list of more recent acts of terror: The Boston Marathon bombings by self-styled jihadist brothers upset about U.S. involvement in Afghanistan and Iraq; the Newtown mass murders of 26 children and adults including the shooter's own mother; and the murders of our Ambassador to Libya and three other Americans by al-Queda affiliates. North Korea's leader repeatedly threatens to nuke the U.S. mainland, with provocative movement of missiles. WHY? And what can we do about it to protect...