Thucydides on Crisis

I am about to teach Thucydides' History of the Peloponnesian War, and the following excerpt caught my eye concerning general approaches to new, complex crises:

And it is just as true in politics as it is in any art or craft: new methods must drivfe out old ones. When a city can live in peace and quiet, no doubt the old-established ways are best: but when one is constantly being faced by new problems, one has also to be capable of approaching them in an original way. (1.71; trans. Rex Warner)