The good news is that Card has placed himself firmly on the side of lawful good, changing his previous alignment of lawful evil. There's no creepy character torture. There are a number of good action sequences (unfortunately, all of them are in the first half of the book). There's a fine "Oh, my God!" moment-- something I think is absolutely required of real world political thrillers.
It may be a surprise to those who read Card's editorials that gay marriage is presented as probably a bad idea, but those who get worked up against it are presented as loons.
I'm announcing Lebovitz's Limit: a test for fiction-- do the good guys commit torture? Empire almost passes. Details and other spoilers are under the cut.
However, the book is set in Bizarro America......
In particular, military robots are used to conquer Manhatten. (The appearance of the first robot is the "Oh my God!" moment mentioned above. While the conquest is easier than it should have been-- if it's obvious that the robots are targetting people in uniform, the police would have gotten into street clothes. This doesn't seem to occur to anyone. Also, I think some interesting things could have been done to the robots with construction equipment, not to mention dropping heavy objects from high places.
In any case, the story has it that the government of New York and various other cities and some blue states reach an immediate accommodation with the Progressive Restoration. This is insanely implausible.
The presentation of Princeton as far-left only seemed surreal, especially the notion that there's only one isolated soldier/conservative in the classes.
The torture issue: the good guys do *not* use torture for interrogation. This is something of a relief in an action-adventure novel. However, both of a man's arms are broken in order to restrain him. This seemed more like red meat for the reader than a practical necessity. (He was given morphine, but not enough to really control the pain.)