It was the rise of Athens and the fear that this instilled in Sparta that made war inevitable. - Thucydides

You have become regular speech-goers, and as for action, you merely listen to accounts of it; if something is to be done in the future you estimate the possibilities by hearing a good speech on the subject, and as for the past you rely not so much on the facts which you have seen with your own eyes as on what you have heard about them in some clever piece of verbal criticism. Any novelty in an argument deceives you at once, but when the argument is tried and proved you become unwilling to follow it; you look with suspicion on what is normal and are the slaves of every paradox that comes your way. The chief wish of each one of you is to be able to make a speech himself, and, if you cannot do that, the next best thing is to compete with those who can make this sort of speech by not looking as though you were at all out of your depth while you listen to the views put forward, by applauding a good point even before it is made, and by being as quick at seeing how an argument is going to be developed as you are slow at understanding what in the end it will lead to. What you are looking for all the time is something that is, I should say, outside the range of ordinary experience, and yet you cannot even think straight about the facts of life that are before you. You are simply victims of your own pleasure in listening, and are more like an audience sitting at the feet of a professional lecturer than a parliament discussing matters of state.

History is philosophy teaching from examples.

[W]e must make up our minds to look for our protection not to legal terrors but to careful administration.