[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."

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

A mutual friend, Benjamin Rush, brought [Tomas Jefferson and John Adams] together in 1812, and they went on to exchange letters for the rest of their lives. But in their correspondence they tended to avoid the most controversial issues, such as slavery.

Again and again [Tomas] Jefferson deftly sidesteps many of [John] Adams's often provocative remarks. They both felt the correspondence, which was written for posterity, was too important to risk by being too candid with one another.

[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."

This rationale, which justified the mixed constitution of Great Britain, might have made some sense in 1776, but by 1787 most American thinkers had come to believe that all parts of their balanced governments represented in one way or another the sovereign people. They had left the Aristotelian idea of mixed estates - monarchy, aristocracy, and democracy - way behind. [John] Adams had not, and his stubbornness on this point caused him no end of trouble.

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.