The Democratic National Committee and members of Congress are turning to Hollywood for help with voter turnout and messaging ahead of the midterm elections and 2020 presidential campaign, quietly consulting with a group of actors, writers and producers here. DNC Chairman Tom Perez, several House members and other top elected officials have already met with the group, formed by members of the entertainment industry in the wake of the 2016 election, that participants liken to a TV writers’ room, complete with producers of such programs as “Veep.” The existence of the group and details of the meetings have not been...