Louis XVI

The king who bankrolled the American Revolution. Even before the alliance he quietly approved the secret aid — money and cannons smuggled through Beaumarchais's cover company — and after news of Burgoyne's surrender at the Battle of Saratoga reached Paris, he made it official: in 1778 France formally recognized the United States, and French fleets, armies, and loans carried the war all the way to Yorktown.

The irony is hard to miss: the debts from that war helped bankrupt France and light the fuse of its own revolution, which ended with the king on the guillotine in 1793. The monarch who helped a republic get born was undone by the idea he'd paid for.

I met him at the Saratoga visitor center, in the panels tracing the French thread of the war — received there alongside Benjamin Franklin at Versailles, months after Saratoga changed his mind.