The quote "If men were angels, no government would be necessary" was said by James Madison. He wrote this in The Federalist No. 51, where he discusses the nature of government and the necessity of controls and checks because humans are not perfect. Madison explained that if men were angels, there would be no need for government, and if angels were to govern men, there would be no need for controls on the government itself. The quote highlights the need for government structures that can control both the governed and the government itself to prevent abuse of power.