6 ideas
Frederick holds that the sovereign is not the owner of the state but its first servant, placed in power to secure the welfare of the governed. On this view, legitimacy comes from performing that function, and a prince who uses the state for private glory has broken the terms of his office.
Frederick rejects the idea that statecraft is exempt from ordinary ethics and condemns perfidy, cruelty and bad faith in a prince as wrongs that his power makes more harmful. He does not make the rule absolute, though: in chapter 18 he allows a prince to break a treaty when necessity and the preservation of his people require it.
Frederick condemns wars of conquest undertaken for glory or territory, because subjects pay for them in blood and ruin. He accepts defensive wars and wars to honor alliances. He also accepts precautionary wars meant to check a power that is growing dangerous, even where no attack is imminent.
Frederick argues that treachery and cruelty wear down the trust and loyalty a ruler needs. Deception works once, but a known deceiver loses allies and faces subjects who obey only while forced to. A reputation for good faith is therefore the more durable asset.
Against Machiavelli's claim that it is safer to be feared than loved, Frederick contends that fear-based rule is brittle. Frightened subjects wait for a chance to defect, while those who benefit from just rule defend the ruler willingly.
Frederick locates a state's real power in a thriving, well-governed population, not in territory or treasure seized by force. Agriculture, commerce, the arts and fair justice raise the state's capacity, so good government is also sound strategy.