From hero to traitor: Benedict Arnold’s day of infamy - National Constitution Center

On September 21, 1780, Benedict Arnold gave British Major John André the plans to West Point. An excerpt from the article:

"On September 21, 1780, Revolutionary War hero Benedict Arnold turned his back on his country in a secret meeting with a top British official. So how did Arnold, with his patriot’s pedigree, become the most hated man in America?

Historians have several theories about why Arnold became a traitor: greed; mounting debt; resentment of other officers; a hatred of the Continental Congress; and a desire for the colonies to remain under British rule. The September 21 meeting with British Major John Andre was a disaster for both men.

Arnold was descended from a Rhode Island founding family. The major general led and served with honor at Ticonderoga, Quebec and Saratoga. But Arnold often fought with other officers and Congress. American commander George Washington understood Arnold’s shortcomings but valued his usefulness on the battlefield.

Arnold was wounded seriously at Saratoga, and Washington put Arnold in charge of the city of Philadelphia after the British ended their occupation. When Washington then asked Arnold to rejoin his Army as a top commander, Arnold instead requested command of the Hudson Valley region and the facility at West Point, New York.

Andre was a top aide to British commander Sir Henry Clinton. The young major also led the British spy network and had been in secret talks with Arnold for some time.

Within a month of their meeting, Andre was executed under orders from American commander Washington for espionage, while Arnold fled to a British side that didn’t exactly welcome him with open arms. The British, and many Americans blamed Arnold for the death of the popular Major Andre, and many people resented that it was Andre, and not Arnold, who swung from the gallows."