Warriors from the Ashes — William W. Johnstone

Rebels wage war again a Nazi madman, a Latin American warlord, and a corrupt president in a post-apocalyptic desert -- from a USA Todayâ€"bestselling author.
 
Under the command of Ben Raines, the Southern United States of America have defeated all comers -- and carved out a stronghold in the Southwest desert. But now, two powerful forces are crashing in against the rebels from the north and the south. A cataclysmic war on two fronts has begun...

The glorified thugs of the New World Order have seized Mexico City, and Bruno Bottger's mercenary army has joined forces with the Nicaraguan and Honduran troops of former Sandinista Perro Loco. Meanwhile, U.S. President Claire Osterman is attacking by land and air from the North. Now, Ben Raines has no choice but to strike back with everything he's got. In a firestorm of bullets, bombs, and a new generation of horrifying tactical weapons, one small army must stand against two enemies...and the odds are just about even.
 
Thirty-first in the long-running series!