Divination Ignored

Though this example is only useful to my argument by analogy, since it does not concern the Peloponnesian War, it's too good not to write down.

Publius Appius Claudius Pulcher was a rich Roman and a general.  Before an important naval battle, he was compelled to consult the sacred chickens.  As the superstition went, if the chickens ate the food put out for them, the gods approved of the battle and the fleet could attack.  If the chickens did not, however, the battle must be put off.

For whatever reason, the chickens did not eat.  Exasperated and eager for battle, Claudius Pulcher grabbed the chickens and flung them into the sea, exclaiming (or so the story goes), "if they will not eat, well, let them drink!"  He then attacked.  

This story captures much of what my thesis is about - divination was a convenient thing, but, at least for leaders, not powerful enough to dissuade them from greater plans.  Pulcher was going to attack that day, signs be damned.  

Also tellingly, Pulcher's men were reluctant, being more superstitious than the patrician.  When the Romans lost the battle, Pulcher's impiety was blamed.  According to this amusing website (which I have not verified in any way), Pulcher's relative was even fined later for daring to suggest that other Roman armies would have been better off with him in charge.