Yep, a Harry Turtledove yarn. There's a less well-known Science Fiction alternative history in which the postwar US cavalry is better equipped with repeating carbines, but the Aboriginies have developed heavier-than-air aircraft.
And then there's my twisted history, in which General George Patton, about to return to the US after being relieved of command of Third Army, hears the news of the crash of Ike Eisenhower's transport plane, with most of his headquarters staff aboard. That changes things around just a tad.
I like the things Harry writes about.
I just wish he was a better writer.