" The doctrine that bears Monroe’s name—that the United States opposes all European intervention in the Western Hemisphere—owes much to the work of Monroe’s secretary of state, John Quincy Adams, who was instrumental in the formulation of the policy. But it was also at least partly of Jeffersonian inspiration. In Jefferson’s case, it was fitting that a man who had spent his life in pursuit of control would extend it as far as he could in the service of his nation, leaving a kind of last declaration of independence. This time it was a matter of policy, not of revolution. It was a declaration all the same. I "

― Jon Meacham , Thomas Jefferson: The Art of Power