58 people have been murdered by a single gunman in Las Vegas. This is the greatest mass murder in American history, breaking a grim record set last year… We always want to know why these senseless murders happen. But usually the answer is unsatisfactory and unsatisfying. Sometimes people do senseless things… Dennis talks to Mary O’Grady, columnist for WSJ who specializes in the Caribbean, Latin and South America. The topic is Puerto Rico and the federal response to the hurricane.