There were a few causes that led to the American declaration of war against the British in 1812. At this time Britain was at war with France and attempted to cut off trade between the US and France. Additionally at sea the British were impressing US seamen or forcing them to become part of the British Royal Navy. Another cause of the war was that the British were helping to arm Native Americans to prevent American expansion westward. As a result of these forces the U.S. eventually went to war with Great Britain.