Empire has been nominated for the Prometheus award. It stands a chance as a cautionary tale like 's It Can't Happen Here. The story covers a plot (with tentacles in the White House) to overthrow the government and bring about a left-wing coup. The action is intense, but the politics is strained. Like Lewis' novel, the point (as Card explains in an afterward) is to convince us that it wouldn't take much to turn our current heavily factionalized politics to open warfare.'s
The story reveals that far-left and far-right groups have been preparing plans in secret for years to take control of the government violently if it should become necessary (because the other side has gotten too much control.) The leftist radicals apparently have the advantage, since they have an extremely wealthy fanatical backer who has been funding the development of new high-tech weapons and staffing and training an army to use them. This part unfortunately reflects the fact that the backers of Card's project are game developers; the new weapons are several steps ahead of what the uniformed military has access to, but would play well on the video game consoles.
The viewpoint characters are sympathetic, well-trained special ops soldiers, and are patriotic to a fault. Their loyalty is to the nation and its legitimate leaders. The action is intense. But ultimately, the story falls short of being a cautionary tale. The motives of extremists on both side are hard to fathom; they want control of the levers of power to prevent the other sides extremists from doing something bad, but it's not clear what. After the conspirators take control of New York City and get sympathetic resolutions from a few state legislatures, they don't make any visible changes in anyone's lives.
At least Sinclair Lewis showed that the fascists who took over would have to suppress dissent brutally and ruthlessly in order to maintain control. In Card's novel, life goes on as before. At the end of the novel the viewpoint characters suspect the newly elected president of having helped orchestrate the entire coup in order to ensure popular support for his own election as a peacemaker. But they can't find any indication that he has dastardly designs to justify the conspiracy they are looking for.
The attempt at a coup and rebellion were short-lived, caused only a handful of deaths and a moderate amount of damage, and didn't have any impact on everyday life. As a cautionary tale, it's not much to worry about. If the protagonists hadn't done such a good job of protecting the nation, an extremist megalomaniac might have taken over the government, but Card's novel doesn't explain why that was something to worry about.