PoD-of-the-Day #e (29 February 2008): Because I was recently rereading
The Peace of Nicias and the Sicilian Expedition, I decided to develop a certain idea that has been thrown around a bit. The Battle of Mantinea (418 BC) goes differently; the elite Argive hoplites charge the gap in the Spartan lines, and the Lacedaemonian army is broken up and smashed, with King Agis II barely rallying the remnants to retreat back to Laconia. This, I believe, is a much better moment to elevate Alcibiades' rising star than the Sicilian Expedition, because of the geopolitical error made in attacking Syracuse in the first place. With this success, and because the Argives will receive four thousand more troops following the successful conclusion of the battle (in OTL they arrived too late and were only able to defend the Argolis itself from the victorious Spartans) they will be able to follow up this victory. Alcibiades, being present at the scene, will be able to win accolades as he pretty much shatters the Peace of Nicias but wins serious advantages in its place. From Pylos the Athenians will be able to provoke a helot revolt in Messenia and detach that from the seriously weakened Spartans; the Spartans will likely as not be forced to come to terms with the Athenian and Argive-led democratic Peloponnesian alliance that was only just coming together by the time of the battle itself. Perhaps they will need to fight another battle, but by this time the opportunistic Athenians will have sent more aid to the victorious Argives and the two will actually outnumber the Spartans due to the losses from the Archidamian War and from the recent Battle of Mantinea. They will also lose manpower in order to make up for the loss of their helots. Sparta will need to end the war, likely by 416 BC, and will lose quite a few major concessions (this is the most danger Sparta has been in throughout the course of the war), such as splitting off from Corinth and Thebes (the dissolution of the Peloponnesian League was one of the major Athenian war aims) and ceasing the Spartan intercourse with the Macedonians, so the Athenians can recover the Chalcidice and their posts in Thrace. Finally, Messenia will be detached from Sparta so as to weaken the Lacedaemonians and to serve as a cordon sanitaire to wall them off from the rest of Greece, along with Tegea and the Argolis itself. The end result with respect to Sparta is that it will be severely weakened, just like it was after the 371 Battle of Leuctra and the 362 Battle of Mantinea (!), and likely unable to exert major influence in Greece proper with the loss of the critical Messenian territories.
As for Alcibiades, he will have major political weight following his brokering of the replacement for the Peace of Nicias. Nicias himself will have been politically outmaneuvered and will likely lose his post as the leader of the "peace" faction. With this new victory, Alcibiades himself will reach the position of a new Pericles as "First Citizen", vanquisher of Sparta, succeeding where even his illustrious adoptive father could not. We will likely see some Caesarism from him, but blatantly abolishing the democracy will not work; it took defeat at Syracuse and revolt in the empire to drive the Athenians to the revolution of the Four Hundred. Overt rule by one man is just too unlikely at this juncture. With his political power, though, Alcibiades can play the democracy into getting what he wants by ostensibly submitting his decision to the people.
He will have ample opportunity over the next few years to exercise it. The five years between 415 and 410 are probably going to be spent reclaiming the valuable Thracian portion of the empire and mending relations with the Macedonians. The Chalcidice has lots of wood, after all, and ships need wood. While Sicily will be slowly dominated by Syracuse, it will not be extending its power very quickly. Athens will have plenty of opportunities to intervene there. Without the distraction of Sparta and with the incompetent Nicias discredited, Alcibiades may well be able to seize Syracuse and subordinate the greater party of the Sicilian breadbasket. Megala Hellas has a good chance of falling into the Athenian lap after that. As for Greece itself, Corinth and Thebes, while detached from the Spartan alliance, will still not particularly like Athens. Athens will be a catalyst for another alliance between those two states (Sparta is likely going to be too weak to act in the near future with any sort of success; Argos and Messenia will be able to keep it in check anyhow). Meanwhile, the Great King never much liked Athens, and it will be getting too powerful again. Tissaphernes will be unleashed against the Athenians to aid the Corinthians and the Thebans, probably in the middle 400s.
Now, Thebes and Corinth together aren't that weak at all, and with Persian assistance they could make trouble. Corinth does have a respectable navy after all, and they could try to raise Cain with the Persians in the Athenian Empire. But frankly, Athens' navy just has too much of a lead on her enemies for them to be able to win significant successes. At the same time, she has Alcibiades, a general of no small skill, at her head, and his comrades Thrasybulus and Demosthenes (who wouldn't, of course, die at Syracuse) as generals as well. Thrasybulus in particular is one of the greatest military minds in the world at this juncture (look at the OTL victories of Cyzicus and Arginusae) and will be able to beat up on Tissaphernes. In Boeotia itself, Thebes is sort of bereft of any good generals, and at the same time will be menaced from the rear by Athens' empire in Aetolia and Acarnania, and the Athenian ally of Thessaly. We'd have a war of maneuver between the Corinthians and the Athenians around the Megarid and Mount Cithaeron. Athens has a central position, though, and they do have superior generals. We might even be able to get Iphicrates in there. Athens also is able to draw on Thracian light infantry from her conquests in the Chalcidice and on the Thracian coast. Since in a one-on-one fight, peltasts > hoplites (see OTL Battle of Lechaeum), Athens should be able to get the upper hand here as well. The Greek front will be closed by 395 BC, while the Persian war will probably drag on longer. Athens will maintain her position in Ionia with her impressive navy, and perhaps will be able to seize Cyprus, which liked to revolt around this time. In any event, Persia will probably have a redux of the fifth century war with Athens, with the war slowly petering out after a few decades.
This Athenian Empire will not survive for ever, though. Megala Hellas will be pure hell to hold on to, especially with Carthage regaining her power around this time, for example. Athens has much better experience at maintaining hegemony than the Spartans or the Thebans did, so it will last quite a bit longer than either of theirs did, especially since it is a thalassocracy with the attendant good chances for survival that has. If a proper genius ascends to the post of First Citizen in the next few years, Athens, not Macedon, could take advantage of the extremely weakened state that Persia is in, establishing a sort of hegemony over Anatolia, the Levant, and Egypt, because those areas are profitable and close to the sea. Darius III's compromise very well could work, with the Persians getting about the stuff that Parthia used to have. Greek influence will be much less widespread, especially in Persia itself, but in the areas that Athens does grab, it will probably be more concentrated. No Hellenistic Kingdoms this time around, probably, unless Egypt breaks away. In the meantime, we have Rome off to the west, starting to get powerful, and when they beat the Samnites and run up against the Athenians' protectorates in Megala Hellas/Magna Graecia, things could get interesting, and Carthage may be able to pick up some of the pieces.
Thoughts? Comments? Death threats for this not being part of the TL I'm writing?

p)