When that district was created in 2002, a Republican, Max Burns, initially won it (it was, curiously, designed to elect a Black Democrat when the Dem legislature and Dem Governor overplayed their hand at trying to draw a Dem federal majority). Barrow lucked out by narrowly beating Burns in 2004. Burns would’ve won it back in ‘06 had it not been for a toxic anti-GOP environment. Barrow actually survived the redistricting in 2012, but the national anti-Dem climate in 2014 is what finally did him in.
The GOP-dominated Georgia legislature tried to gerrymander Barrow out of his seat twice. Each time he foiled them. They finally succeeded the third time. I know the Barrow family well, but I am only a very casual acquaintance of John’s.