"A Diary from Deimos" by Michael Alexander appeared in the September/October issue of Fantasy & Science Fiction. "In a story that parallels the War Between the States, settlers of Mars, depicted as Southern plantation owners, secede from the Earth Federation when the Federation declares that sentient robots, depicted as slaves, will be granted rights equal to humans." (Another of Mr. Alexander's tales, "The Children's Crusade," was reviewed in Songs of Eretz on July 19, 2012).
I especially love science fiction stories that describe something that might actually happen, and "Diary" is one of these. It is, of course, a satirical piece, but in every satire there is at least a colonel, ahem, kernel of truth. We will eventually reach the point where robots created by man to serve man will be just as sentient as man. Will we keep them as slaves, or will we set them free?
"Diary" is not the first time that this topic has been explored. In The Measure of Man, one of my favorite episodes of Star Trek TNG, the Enterprise's sentient robot, Data, is put on trial by the Federation of Planets to determine whether he will be treated as a man or as a machine. Asimov also has addressed this issue in his robot stories, Caves of Steel, et al.