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.

If history teaches anything, it teaches humility.

[John] Adams's letters reveal his persistence and determination to win over the Dutch against all odds and to convince them and the other peoples of Europe of the potential greatness of the United States and of the importance of the Revolution to the world.

As early as 1776, [John Adams] expressed his doubts about America's capacity for virtue. "I have seen all along my Life, Such Selfishness, and Littleness even in New England, that I sometimes tremble to think that, altho We are engaged in the best Cause that ever employed the Human Heart, yet the Prospect of success is doubtfull not for Want of Power or of Wisdom, but of Virtue."

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.

[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.