Bill Cassidy did not want to talk about Robert F. Kennedy Jr. Last month, as we shuffled through the U.S. Senate subway, a subterranean corridor connecting lawmakers’ offices to the Capitol, the senator from Louisiana was fielding rapid-fire questions from reporters about two of his favorite topics: drug pricing and college sports. But I asked him about his least favorite: Did he regret confirming Kennedy as health secretary? I was eager to know because, in spite of that decision, Cassidy may