President Thomas Jefferson was an agrarian at heart, and had little sympathy with careers in seamanship or foreign trade in sailing vessels. So, after seeing the increasing seizure of our seamen by the British (who impressed many into their ships)and Napoleon seizing our vessels going to England (for their cargoes, Jefferson decided to not sell goods to the British or French. Most of our foreign trade was carried on by New England, New York, and the North (in general). Southerner Jefferson never had use for these groups (except for a handful of Northern Democrat-Republican allies in New York, New Jersey, and Pennsylvania). The others were mostly the enemy Federalists. So Jefferson did not care that this would hurt America's merchant marine.Adams, a freshman Federalist Senator from Massachusetts decided Jefferson was right, and voted for the Embargo Act.
It almost ruined the economy of New England and this is my problem with Kennedy's decision to choose this incident. In hindsight there was no gain by Jefferson's stupid act. Adams was from the area most heavily impacted, but he apparently did not care for the shipping industry of his native New England. I don't care how brave his vote was on this matter - it hurt too many people. Adams was condemned as traitor to his part of the country. He was defeated for reelection as a Senator.
But his vote was noticed by Jefferson, who appointed Adams to the Diplomatic Corps. He would be our minister to Russia during the Napoleonic Wars, and also the leading diplomat at the signing of the Treaty of Ghent that ended the War of 1812. His work in the diplomatic world led to the post of Secretary of State under James Monroe, and then the Presidency. Given the mileage he got out of the "vote of conscience" he displayed, I just wonder if Adams took a cool, calculated gamble. He was a nationalist, like Jefferson and Madison and Monroe, and he knew the current Federalist Party (once John Adams retired, and Alexander Hamilton was killed) was a regional ostrich with it's head in the sand. Did he use the vote to gain Jefferson's approval (as it did)? In any event the decision to vote on the matter as one of conscience over expedience did not really seem to harm Quincy Adams.