Q. Adams greatest lessons on international relations were likely learned when he was abroad as a young man with his father to France and Britain on diplomatic missions with the likes of Benjamin Franklin and John Jay.
It was there that he learned the massive array of languages (7 if you include Latin and Greek) and saw the terror that ambitious foreign policies could reap on countries. He saw the needless destruction of cities, towns and lives and witnessed the even bloodier revolutions (he was a critic of the French Revolution like his father) that could occur when citizens sought to unseat their rulers by force and create populist utopias.
He felt the United States had enough problems of its own, with internal divisions between the different geographies threatening to tear it apart and external enemies looking to take advantage of any weakness. The best option was to focus on security at home, improve the armed forces but deploy them only for defensive missions. Abroad, he felt the United States should maintain relations with Europe, but not enter into any military agreements or treaties for 'wars of intrigue'.
These fundamental beliefs led him as Secretary of State in the Monroe administration to work with James Monroe to craft what's now known as the Monroe Doctrine.
My favorite quote of his best sums up his beliefs "America does not go abroad in search of monsters to destroy. She is the well-wisher to freedom and independence of all. She is the champion and vindicator only of her own."
It's sadly ironic that the Bush administration called the policy of pre emptive strikes in the Middle East extensions of the Monroe Doctrine, both Q. Adams and Monroe would roll in their graves if they heard that.