It cannot be easy to lead the agency that handles infectious diseases in the midst of an international pandemic. Still, the director of the Centers for Disease Control and Prevention should at least be able to prove she is up to the task. Dr. Rochelle Walensky has repeatedly proved herself unfit and unreliable. She needs to go. Perhaps her worst failure, however, was her wishy-washy approach to school reopenings. Walensky switched her position on whether social distancing in the classroom was necessary, not once, not twice, but three times. First, she said that three feet of social distancing would be...