Operation Annihilation

Recon 9, a group formed by veteran Air Force pilots who'd escaped a Russian POW camp, faces a world devastated by plague, a desultory worldwar, and a widespread civic collapse. Recon 9 follows a trail of bodies across Texas, discovering that west Texas put the wild in the wild west. To catch the Russian agent they have to deal with bandit gangs, groups of homicidal maniacs, and military holdouts. The agent is carrying out a program called Operation A or Operation Alpha.
To them, it seems to be: OPERATION ANNIHILATION