[John Adams] is impressed with [Tomas] Jefferson's learning, but noted his silence during the debates in the Congress: "I never heard him utter three Sentences together."

[John] Adams's letters to [his wife] Abigail are wonderful. In his letters, he is loving, humorous, preachy, learned, and saucy. He speaks to her with almost complete abandon, revealing all of his sensuous and vulnerable nature.

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."

[John Adams and Tomas Jefferson] shared experience in 1775 - 1776 in bringing about the separation from Britain and their service in Europe cemented a friendship that in the end withstood the most serious political and religious differences that one could imagine, especially their differences over the French Revolution. It was probably Jefferson's obsession with politeness and civility that kept the relationship from becoming irreparably broken.

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] always felt that his contribution to bringing about independence went unappreciated, especially after the 1790s when [Tomas] Jefferson began to be lauded as the "author" of the Declaration of Independence.