The history of the conflict between Ancient Athens and Sparta, especially during the period of the Peloponnesian War, shows that when argumentative democracies (like Athens) go to war, criticism tends to overpower conquest. The nation’s politicians and intellectuals criticize the war, they turn public opinion against the war, and force the rulers and military commanders to surrender the conquests that the soldiers have made in the battlefield.
The doctrine that Sparta was a bigger threat to Athens than Persia and hence it must be destroyed was first proposed by the Athenian general Themistocles in 479 BC, a year after the Battle of Salamis, in which the Athenian navy defeated the Persian navy. Themistocles could not convince the Athenians to go to war against Sparta, and in 472 BC, he was ostracized and banished from Athens. Cimon, the Athenian politician and general who came after Themistocles, wiped out the remaining Persian encampments in the Greek lands but he had no desire to wage war against Sparta. He tried to develop a friendly relationship with the Spartans.
The democratic revolutionary Ephialtes became the leader of Athens after Cimon was ostracized and banished from Athens for ten years beginning in 461 BC. The reforms of Ephialtes led to the power passing into the hands of the citizens—the Council of Five Hundred, the Assembly, and the popular law courts. However, within a year of his reforms, Ephialtes was assassinated by the Athenian aristocrats. His assassination paved way for the rise of the second democratic revolutionary of this age, Pericles who used his oratory and loud voice to dominate the Athenian assembly and make a case for war against Sparta. The Peloponnesian War (431–404 BC) began when Pericles was at the helm, but he died in 429 BC. The major battles of the Peloponnesian War were fought under Cleon.
During the twenty-seven years of the Peloponnesian War, Athens was a divided society. There were noisy debates in the Athenian assembly on different aspects of the war. Several politicians and generals were ostracized and exiled. There were a number of democratic revolutions and aristocratic counterrevolutions. There were betrayals and assassinations.
Being a democracy, Athens could not control the criticism of its war against Sparta. The Athenian politicians and generals could not develop a clear strategy for the war. They could not define a set of goals for which they were fighting. They often worked at cross-purposes, and tried to use the war for improving their own hold on Athenian politics. Alcibiades, the Athenian statesman, orator, and general, changed his political allegiance several times—sometimes he was with Sparta and sometimes with Athens. One reason for which Athens lost the war against Sparta in 404 BC is that its argumentative democratic system did not support its soldiers in the battlefield.
Democracies should not go to war unless they are ready to fight a war on two fronts—the external war against the enemy nation and an internal war against the intellectuals and politicians who would derail the war by criticizing it.