Final answer:
The War of 1812 was caused by British interference with American trade, including the practice of impressing American sailors into British naval service.
Step-by-step explanation:
The cause of the War of 1812 was multifaceted, but one of the direct causes was British interference with American trade. While the French troops in Canada, Spanish forces in Florida, and support for the Confederacy are not accurate causes for this war, the actions of the British, particularly their naval policies, did play a significant role. The British impeded American trade with Europe by cutting off trade routes and by the practice of impressment, wherein American sailors were forced into service on British ships. This practice was a violation of American sovereignty and a direct cause of the conflict.