The War Years #3: The Jupiter War by Gregory Benford, Bill Fawcett

It’s the 2050s and Earth is divided into two enemy the UN nations – the United States, Europe, Russia and Japan – and the Confederation of States – South America, South Africa and Arabia. But they have taken their animosity into space, each claiming territories farther and farther out in the solar system, until both reach and lay claim to the wealth to be found in Jupiter’s moons. And then finally, inevitably, the Jupiter war begins.