The militaristic system the Spartans put in place was a web that caused them grief as long as it existed. I call it a “devil’s bargain” because Sparta willingly exchanged culture and normalcy for military superiority. As Aristotle said,
“The whole regime is directed toward securing a high standard in one department only, namely the military field. This is, of course, the key to victory; so the Spartans did well while they were at war but came to grief when they had acquired an empire. This is because they did not know what to make of peace time. They had made their training for war paramount to training for anything else.”
Couldn’t we say without joking that the Messenians had the Spartans under their control in equal proportion to the reverse? After all, the Spartans needed an army (8,000-9,000 Spartiates) to protect themselves. What would happen if the Spartiate numbers were attrited to a point below that level? Must Sparta now avoid war for fear that losses would weaken them to the point not being able to defend themselves? Victory would mean more territory to govern with no additional men: defeat would mean the loss of men and greater vulnerability.
This tells us how profoundly they Messenian revolt had affected the Spartan psyche, for as Toynbee says,
“It (the Messenian revolt) was so terrible an experience that it left Spartan life fast bound in misery and iron, and it sidetracked Spartan evolution into a blind alley. And since the Spartans were never able to forget what they had gone through, they were never able to relax, and never able to extricate themselves from the impasse of their post-war reaction… They lived on as the obedient humble servants of their own dominion over Messenia from that time forth evermore.”
And what of the impact of war on the balance of government? Since the Damos was made up of Homoioi, the loss of a substantial number would destroy that body and its role in balancing the other branches.
And there was still a greater Spartan nightmare than the loss of Homoioi or a Helot revolt. What would happen if a hostile foreign power would come to the aid of the Helots and fight alongside them? Argos was a likely candidate and it took the Battle of Thyrea in 544 B.C. and Sepeia in 494 B.C. to quiesce her, and allow Sparta to relax. Later, when Athens made a pact with the Helots in 425 B.C, Sparta moved with urgency to secure the peace which ended the first phase of the Peloponnesean War.
Sparta also employed another tactic to protect herself – the Peloponnesean League, which was built up in the mid to late sixth century B.C. Using the armies of allies to leverage her own offered to act as a safety value to lower the pressure of the Helots.
But it wasn’t always a case of diplomacy, because we can see Sparta avoiding war too. One suspects there was more to the late arrival at Marathon and the unwillingness to command the forces of libration in 479 B.C, than merely missed appointments. Ultimately, this kind of equivocation would embolden Athens and lead to the Peloponnesean War.