A former congressman battling to reinstate an election for Georgia Supreme Court Justice Keith Blackwell’s seat has subpoenaed Blackwell, the secretary of state, the governor’s executive counsel and the head of the state Judicial Nominating Commission to appear in Fulton County Superior Court Friday.

The subpoenas order them to appear as witnesses at Friday’s hearing on a petition for a writ of mandamus that former U.S. Rep. John Barrow filed last week after he was told he couldn’t qualify to run for the seat. The secretary of state canceled the election on March 1 at the governor’s request, the day before qualifying was supposed to begin.