Settling accounts - drive to the east - Harry Turtledove

Turtledove's alternate history of a century-long American civil war continues . . .

The second book in the Settling Accounts sequence takes the story to 1942, during an utterly different World War II.

The Confederate States of America are locked in a tangle of jagged, blood-soaked battle lines with the United States of America.
In Richmond, dictator Jake Featherston is shocked by what his own aircraft have done in Philadelphia - killing U. S. president Al Smith in a barrage of bombs. But he presses ahead with a secret plan on the dusty plains of Texas, where a so-called detention camp hides a far more evil purpose.

The United States face a furious thrust by Confederate army into Pennsylvania. But with the industrial heartland under siege, Canada in revolt and US ships fighting against the Japanese in the Sandwich Islands, the most dangerous place in the world may be overlooked.