The War of 1812 (18 June 1812 – 17 February 1815) was fought by the United States of America and its indigenous allies against the United Kingdom and its allies in British North America, with limited participation by Spain in Florida. It began when the United States declared war on 18 June 1812. Although peace terms were agreed upon in the December 1814 Treaty of Ghent, the war did not officially end until the peace treaty was ratified by Congress on 17 February 1815. Tensions originated in long-standing differences over territorial expansion in North America and British support for Native American tribes who opposed U.S. colonial settlement in the Northwest Territory. These escalated in 1807 after the Royal Navy began enforcing tighter restrictions on American trade with France and press-ganged men they claimed as British subjects, even those with American citizenship certificates. Opinion in the U.S. was split on how to respond, and although majorities in both the House and Senate voted for war, they divided along strict party lines, with the Democratic-Republican Party in favour and the Federalist Party against. News of British concessions made in an attempt to avoid war did not reach the U.S. until late July, by which time the conflict was already underway.