If Athenian strategy was to destroy the Peloponnesian League, the best strategy for Sparta was to defend the league by keeping its promises to its allies, before it lost them, even if that meant going to war before Sparta was fully prepared.
Not only had the Athenians used the letter of the arbitration clause in the Thirty Year Peace to undermine the spirit of the treaty and to expand to Corcyra and potentially far beyond in the west, where no one in the Peloponnesian League had ever intended they should go.
From this point of view, he meant to win by not losing, holding out behind the walls of Athens, maintaining control of the sea, avoiding direct battle with Peloponnesian ground forces of equal or greater strength, keeping the Peloponnesians off balance and lifting morale at home with raids on the Peloponnesus, and avoiding new wars of conquest while still at war with Sparta and the Peloponnesian League. (19)
If Corinth left the Peloponnesian League, Athenian power relative to the Peloponnesian League (Pericles's primary adversary) would grow diplomatically, not merely through the alliance with Corcyra but also by dividing Sparta from Corinth, its chief and wealthiest ally and the only one with a significant navy, and, not least important, by reducing its access to northern Greece.
All Athens had to do to break up the Peloponnesian League and escape from its containment was outlast Spartan will to wage war, though it might shorten the length of time it could take Sparta to sue for peace with a judicious mix of defensive and offensive operations.
Pericles's first speech is cautious; his second proud, defiant, and hubristic; his last over the top in a manner that explains why his ward Alcibiades, despite his recklessness, was Pericles's natural heir, the one who best understood that Pericles along with many others had been thinking about Italy and Sicily from the beginning, just not ready to go west until he had broken up the Peloponnesian League.
It would follow naturally on such actions that the new order was sealed with an exchange of oaths, guaranteeing support, and it may be posited that the sixth-century form of the Peloponnesian League was essentially a series of defensive alliances
But if the origin of the Peloponnesian League was no more than a set of defensive alliances between friends, how could Herodotus, it will be asked, have described such amiable relations as subjection?(43) Indeed it has been held that the original condition of the member states was a one-sided obligation 'to follow wherever the Lacedaemonians lead', though the reason why states should put themselves in such a condition is unstated.(44) So Herodotus' view here needs explanation.
The nature of the Peloponnesian League is well illuminated by what Xenophon has to say about the settlement of Mantinea in 385 (Hell.
In the full-blown Peloponnesian League, in the case of military action within the League, as already remarked, there was no debate.(50) Without further ado Sparta called up the members of the League and proceeded to do what was necessary.
But when the Peloponnesian League we meet in Thucydides was organised, a League based no longer on mere defensive alliances, and so requiring a method of deciding whom to attack and when to make peace, this solitary occasion provided the precedent.
When then was the full Peloponnesian League organised?