The statement <em>"Observing what happened to the Spartans and the Romans</em> <em>shows that it is best to destroy a newly acquired state that is accustomed to freedom." </em> best summarises the central idea of the paragraph, and it is <em>supported by the passage</em>: "...to hold it they were compelled to dismantle (demolish; tear down) many cities...there is not safe way to retain them otherwise than by ruining them."
