Whatever "Gone with the Wind" might preach, the aristocracy was in serious financial difficulty before the war, but after the war it managed to regain economic control, thanks to large injections of Northern and British capital.  With renewed economic power came a return of political power, even before the end of Reconstruction, which simply finished the job.  I highly recommend a book titled "Ballots and Fencerails", which focuses on Reconstruction in the Lower Cape Fear in North Carolina.