Question

Do you think Machiavelli was right when he said that a ruler must do whatever necessary to maintain power?

Answer 1

Sure. It's up to the people themselves to ensure that "whatever necessary" always translates to "serve the maximum long-term good of the people." If the people routinely gather together and cut the head off any ruler that does not follow this prescription, then that ruler, in order to preserve his rule and his life will strive to do his best for the people.