Two months ago, a Nevada jury convicted O.J. Simpson of kidnapping and armed robbery in a botched effort to recover sports memorabilia from peddlers last year. In a Nevada courtroom today, shackled and dressed in a blue jump-suit, he was sentenced to a minimum of 15 years in state prison. Judge Jackie Glass insisted she was not punishing him for anything else. Former federal prosecutor Laurie Levenson, now a professor at the Loyola University School of Law, has followed this case and the infamous trial in 1994, when a jury acquitted Simpson of killing his ex-wife, Nicole and her friend, Ron Goldman.