Adam Clarke on Proverbs 28:2

Many are the princes - Nations, as nations, cannot be judged in a future world; therefore, God judges them here. And where the people are very wicked, and the constitution very bad, the succession of princes is frequent - they are generally taken off by an untimely death. Where the people know that the constitution is in their favor, they seldom disturb the prince, as they consider him the guardian of their privileges.

But by a man of understanding - Whether he be a king, or the king's prime minister, the prosperity of the state is advanced by his counsels.