In June 1780, Clinton sent 6,000 men under Wilhelm von Knyphausen to retake New Jersey, but they were halted by local militia at the Battle of Connecticut Farms; although the Americans withdrew, Knyphausen felt he was not strong enough to engage Washington's main force and retreated. A second attempt two weeks later ended in a British defeat at the Battle of Springfield, effectively ending their ambitions in New Jersey. In July, Washington appointed Benedict Arnold commander of West Point; his attempt to betray the fort to the British failed due to incompetent planning, and the plot was revealed when his British contact John André was captured and later executed. Arnold escaped to New York and switched sides, an action justified in a pamphlet addressed "To the Inhabitants of America"; the Patriots condemned his betrayal, while he found himself almost as unpopular with the British.