When lawyers from around the country face off Saturday in a Marietta courtroom over a lawsuit against General Motors, their first argument will be over whether they should even be there.

GM’s lawyers will be asking Cobb County State Court Judge Kathryn Tanksley to throw out a previously settled lawsuit filed by Kenneth and Mary Elizabeth Melton over the 2010 death of their daughter, Brooke, a 29-year-old nurse. The Meltons allege that their daughter died because of a defective ignition switch in her 2005 Cobalt that suddenly shut off the car’s power in traffic, leading to a crash and a rollover.