How does Will claim to have gotten Ted's dad to vote Republican for the first time?

Will says he told Ted, Sr. that he had better vote Republican unless he wanted to see the country ruined. Will says Ted said he couldn't because his granddaddy was a Captain in the Confederate Army and his momma was the head of the Houston U.D.C.. Will says he convinced Ted to change his vote by telling him the Civil War was fought over states' rights and Republicans are now the champions of states' rights.