Short stories by Harry Turtledove
Listing 2 stories.
In a futuristic world, one of the members of a tour group is murdered. Nobody knows who the murderer is, and as the police try to solve the case, they discover that this murderer has far more nefarious plans that can alter the world.
The president of what's left of the United States desperately attempts to defend his country from the Krolp, an evil race of aliens who have proven impossible to beat.