It was the last battle of the Philadelphia campaign, begun the previous year, during which the British had inflicted two major defeats on Washington and occupied Philadelphia. Washington had spent the winter at Valley Forge rebuilding his army and defending his position against political enemies who favored his replacement as commander-in-chief. In February 1778, the French-American Treaty of Alliance tilted the strategic balance in favor of the Americans, forcing the British to abandon hopes of a military victory and adopt a defensive strategy. Clinton was ordered to evacuate Philadelphia and consolidate his army. The Continental Army shadowed the British as they marched across New Jersey to Sandy Hook, from where the Royal Navy would ferry them to New York. Washington's senior officers urged varying degrees of caution, but it was politically important for him not to allow the British to withdraw unscathed. Washington detached around a third of his army and sent it ahead under the command of Major General Charles Lee, hoping to land a heavy blow on the British without becoming embroiled in a major engagement.