I would like to know information on who Locke and Demosthenes really were and what the Warsaw Pact is.
The original Warsaw Pact was the Soviet Union's answer to NATO -- an "alliance" between the USSR and its subject nations in Eastern Europe. Since the Eastern European nations had no choice but to sign and to provide troops, it wasn't exactly analogous, but it was a structure that allowed each of the subject states to maintain an army, even if it was under strict Soviet control. That original Warsaw Pact was the military authority and legal pretext used to justify the quelling of revolutions in Hungary and Poland in the 1950s and the peaceful "Prague Spring" in Czechoslovakia in the 1960s. The threat of the use of Warsaw Pact forces also kept other potential revolts from happening. The Warsaw Pact was also the military force that NATO had to take into account in planning for possible combat in Europe.
In Ender's Game, the supposition is that in building a military force to try to overthrow the rule of the International Fleet, a future Russia assembles an alliance, this time a much more willing one, and deliberately signs the treaty in Warsaw in order to create a New Warsaw Pact that calls up memories of the military strength and world-power role of Russia in the days of the USSR. By then, the atrocities of Stalin would have faded in time, much as the atrocities of Hitler are already fading in the memories of some Germans. He would not have been "rehabilitated," but the world stature of the Soviet Union would be remembered separately from Stalin's misuse of it.
These matters will be much more fully explored in "Shadow of the Hegemon," the sequel to "Ender's Shadow."
John Locke (1632-1704) was an English philosopher whose ideas on government (and on religion and human nature) were strongly influential in the thinking of the founding fathers of the United States. He had a much more optimistic view than Thomas Hobbes, the other most-influential political philosopher of the time.
Demosthenes (385-322 BC) was an Athenian politician who led the opposition to Philip of Macedon in the struggle to keep the Greek cities free of Macedonian overlordship. To those who worship Alexander (the Macedonian party won, after all), he was seen as a rabble-rousing demagogue, playing upon people's fears in order to keep Athens an international backwater. To others, he was a hero of freedom in a losing struggle against dictatorship.
Peter Wiggin chose these two names for his and Valentine's identities online, not because of who they really were, but because of who they were perceived to be. Locke, the image of rational government based on ideals and high principles; Demosthenes, the image of desperate no-holds-barred political struggle for nationalism and against hegemony.