George Washington. Never would have done it without him. And he was the guy who set the precedent of stepping down from office.
John Adams. Was the defense attorney for the British Soldiers involved in the Boston Massacre because he believed they needed adequate representation. Knew that the Declaration of Independence needed to come from a Virginian and not himself as he was disliked. Gave up his chance at a second term as President by avoiding a war with the French, much to the dislike and dismay of his own Federalist Party. A man of great moral fiber, as were so many others.
I would say Washington also. The others were great theorists of the revolution, and essential for it. Washington was the man of action who made their dream a reality.