Scumbag is more popular than I thought.
He is close to the ceiling for possible votes. He is being tested against politicians that Georgia voters don't know so well.
Is it possible for Georgia voters to tire of a crooked R politician even if the State has a strong R lean? If the racial divide in statewide politics in 2014 isn't as strong as it was in 2012, then some Democrat has a shot. A generic R wins against a generic D statewide in Georgia, which means that one of his D challengers would lose an open-seat election. A Republican who defeats Nathan Deal in a primary election beats just about any Democratic challenger.
But there must be some cause for an approval rating in the thirties. Could it be that he is unelectable? Electing him must seem a mistake to many of those who voted for him.
If Scott Walker has a good chance of winning re-election in D-leaning Wisconsin in 2014, then Party label isn't everything.