War of 1812: Although the U.S. Army did not enlist African Americans after the Revolutionary War, the U.S. Navy continued to use African Americans as seamen because of the perennial shortage of white sailors. The African American presence in the navy placed them at the center of the naval incident that led to the War of 1812. In 1807 the British frigate Leopard shelled the USS Chesapeake to locate four escaped British sailors. When the Chesapeake yielded and the British boarded the American ship, they took into custody four sailors, three of whom are William Ware, Daniel Martin, and John Strachan were African Americans previously impressed by the British. Although it was obvious that these men were Americans, the British refused to return them for four years, inciting American public opinion and leading President Thomas Jefferson to close American harbors to British ship. The U.S. could not go to war then because it lacked a serious navy, but the seeds of resentment were sown, and in June 1812 the United States declared war on Britain, citing the impressments of American citizens as a principal reason for going to war.