Key figures: Benedict Arnold, George Washington, Henry Clinton, Peggy Shippen
Summary
Benedict Arnold (January 14, 1741 – June 14, 1801) was a Major General in the Continental Army whose energy and tactical skill made him one of Washington’s most valuable field commanders. By the opening of 1778 he had accumulated a remarkable record: co-leading the capture of Fort Ticonderoga in May 1775, commanding the improvised Lake Champlain fleet that delayed the British advance at the Battle of Valcour Island in October 1776, and delivering decisive blows at the Battles of Freeman’s Farm and Bemis Heights in September–October 1777 that secured the American victory at Saratoga—a victory that directly prompted France’s entry into the war.
1778: Philadelphia Command and Growing Estrangement
When the British evacuated Philadelphia on June 18, 1778, Washington appointed Arnold military governor of the city the same day. Arnold was recovering from the leg wound suffered at Bemis Heights and the command suited his convalescent state. In Philadelphia, Arnold lived extravagantly in the Penn Mansion, mingled with loyalist society, and became romantically involved with Peggy Shippen, daughter of a prominent loyalist family. He also entered into business arrangements with local merchants that his military position made improper, including issuing a pass for a cargo ship, the Charming Nancy, to trade in British-occupied territory.
Pennsylvania’s Executive Council, led by Joseph Reed, filed eight charges against Arnold in February 1779. Washington, caught between his trust in Arnold and the political necessity of appeasing Pennsylvania, forwarded the charges for court-martial. The court-martial, held in December 1779, acquitted Arnold on six counts but found him guilty of two minor charges; Washington issued a formal reprimand in April 1780. To Arnold, the reprimand—delivered by a general he had served loyally—was the final injustice in a long series of perceived slights: Congress had passed him over for promotion in February 1777, crediting others for his victories at Ticonderoga and Valcour Island.
Contact with the British
By May 1779, while still serving as military governor of Philadelphia, Arnold had opened a secret correspondence with British intelligence chief Major John André. Over the next sixteen months he passed information about troop strengths, supply routes, and Washington’s plans. After resigning the Philadelphia command in June 1779, he successfully petitioned Washington for the command of West Point—then used his position to negotiate its surrender to Clinton for £20,000 and a British commission. The plot was exposed in September 1780 when André was captured with incriminating documents; André was hanged on October 2, 1780, and Arnold fled to British lines.
Significance
Arnold’s 1778 service represents the last full year of his unambiguous contribution to American independence. The Saratoga victories he had just delivered brought France into the war (the Treaty of Alliance was signed February 6, 1778) and fundamentally changed its strategic character—making his subsequent betrayal doubly painful to his contemporaries. His case became the American Revolution’s most resonant cautionary tale about the corrosive effects of perceived injustice and wounded pride. The tensions between military authority and civilian oversight that animated his grievances—Congress’s irregular promotions, Pennsylvania’s civil charges, Washington’s formal reprimand—were structural features of the Continental system, not unique to Arnold, which gave his story lasting relevance to American civil-military relations.
His name entered the language as a synonym for treason; the phrase “a Benedict Arnold” was in common use within a generation of his defection.
See Also
- General William Howe (1729–1814)
- John Hancock (1737–1793)
- George Washington (1732–1799)
- Battle of Monmouth
- Treaty of Alliance (France–United States)