I think [John Adams] developed a much deeper suspicion of France and the other European powers than he had earlier. He lost much if not all of the utopian thinking about international politics and diplomacy expressed in his Model Treaty of 1776 and became much more cynical about the world.

History is the queen of the humanities. It teaches wisdom and humility, and it tells us how things change through time.

[John] Adams identified himself with the political theories of [James] Harrington, [John] Locke, and [Charles-Louis] Montesquieu, whose ideas of constitutionalism, he believed, were applicable to all peoples everywhere; they were his contribution to what he called "the divine science of politics."

Perhaps more significant than his experience in Europe, though, was [John] Adams's experience in his own country, and his extensive reading on the history of the English constitution. In 1779, he had an opportunity to try out his ideas by framing the Massachusetts constitution.

I think [John Adams's] influence on the federal Constitution was indirect. Many including James Madison mocked the first volume of Adams's Defence of the Constitutions of the United States in 1787. But his Massachusetts constitution was a model for those who thought about stable popular governments, with its separation of powers, its bicameral legislature, its independent judiciary, and its strong executive.

[John] Adams said his objective in writing his Defence of the Constitutions of the United States and his Davila essays was to counter what he thought was the unfair criticism of the American state constitutions made by the French philosophers, especially [Anne Robert Jacques] Turgot.

I think [John's Adams] descriptions of the personalities of [Benjamin] Franklin and [Tomas] Jefferson and others were pretty accurate. It is only when he felt he was wronged by them that he lets loose his anger and resentment.