After Stalin's death Superman (the other Man of Steel) takes power and eventually every country except the USA have joined his global empire. Local dissidents led by Batman, and President Luthor are the only people willing to oppose a tyrant who can see through walls and travel anywhere in seconds.
The book is an interesting riff on the role of superheroes and power in the world. Even when someone thinks they are doing the best for their country, they may in fact be making things worse. Well worth reading.