"After an appeal was made to the Supreme Court, [abolitionist] Lewis Tappan visited John Quincy Adams at his home in Massachusetts in an effort to persuade 'Old Man Eloquent' to argue the Africans case in Washington," writes Douglas Linder in Famous American Trials. "Former President Adams, then 74 and a member of Congress, at first resisted, pleading age and infirmity. But Adams believed firmly in the rightness of the cause, and eventually agreed... 'By the blessing of God, I will argue the case before the Supreme Court,' Adams was quoted as saying. That October 1840 date he wrote in his diary: 'I implore the mercy of God to control my temper, to enlighten my soul, and to give me utterance, that I may prove myself in every respect equal to the task.'
"The next month Adams stopped by Westville, near New Haven, to visit his clients. He found them all in a thirty-foot-by-twenty-foot room, taken up almost entirely by thirty-six cots. Adams shook hands with [Africans] Cinque and Grabeau, telling them 'God willing, we will make you free.' Later, Adams would receive touching letters from two of the younger Africans, Ka-le and Kin-na.
"On Monday, February 22, 1841, arguments began in the Supreme Court's crowded chamber in the U.S. Capitol... John Quincy Adams began his argument on February 24th. He did not disappoint. He argued that if the President had the power to send the Africans to Cuba, he would equally as well have the power to seize forty Americans and send them overseas for trial. He argued that Spain was asking the President to 'first turn man-robber,...next turn jailer,... and lastly turn catchpole and convey them to Havana, to appease the vengeance of the African slave-traders of the barracoons.' He attacked the President for his ordering a naval vessel to stand ready in New Haven harbor, he attacked a southern intellectual's defense of slavery, and he quoted the Declaration of Independence: 'The moment you come to the Declaration of Independence, that every man has a right to life and liberty, an inalienable right, this case is decided. I ask nothing more in behalf of these unfortunate men than this Declaration.' "
On March 9, 1841, the Supreme Court affirmed, 7-1, lower court decisions freeing the Amistad slaves, who eventually returned to Africa.