The Economist gives the background on this decades-long fight, and why negotiations have so far failed.
"Congressional authorisation seems unlikely, since the combined delegations of Florida and Alabama are so much larger than Georgia's (and there is no guarantee that congressmen from downstate Georgia would side with their Atlanta counterparts). Negotiations are difficult too: since a failure to reach a negotiated consensus would principally harm Atlanta, Alabama and Florida have little motivation to come to the table. Sonny Perdue, Georgia's governor, asked his fellow governors in August for more talks, but all three are lame ducks and will be gone in January.
Still, a negotiated settlement appears inevitable. The alternative is escalating the fight to the Supreme Court, and there is little appetite for that; neither side has a clear road to victory."