Scott Brown was not always the self-assured state senator, lawyer, National Guard officer, triathlete, and Republican candidate for US Senate that he is today. Far from it. He was once a shaggy-haired 12-year-old growing up in Wakefield, drifting into trouble. His parents divorced when he was a year old, he said, and each remarried three times. Asked if he had ever been arrested, Brown, choking up at times, related a story he said he had never told: My mom was on welfare a little bit, and, you know, I lived with my grandparents, I lived with my aunt, whatever. I...