After the Ice Virus hit the population of Earth, it began transforming some people in vampires. Among them, Luthor's daughter. Her sudden transformation happened when Luthor wasn't home. When he returned, his daughter had already killed his wife and son.
As author of vampire books, Luthor was an advocate for their rights and wanted a dialogue with them. As such, he had many meetings with Conrad Holly, the Speaker of the House, who shared much of his views.