In the fall of 1811, Indiana’s territorial governor William Henry Harrison led U.S. troops to victory in the Battle of Tippecanoe. The defeat convinced many Indians in the Northwest Territory (including the celebrated Shawnee chief Tecumseh) that they needed British support to prevent American settlers from pushing them further out of their lands. Meanwhile, by late 1811 the so-called “War Hawks” in Congress were putting more and more pressure on Madison, and on June 18, 1812, the president signed a declaration of war against Britain. Though Congress ultimately voted for war, both House and Senate were bitterly divided on the issue. Most Western and Southern congressmen supported war, while Federalists (especially New Englanders who relied heavily on trade with Britain) accused war advocates of using the excuse of maritime rights to promote their expansionist agenda.
In order to strike at Great Britain, U.S. forces almost immediately attacked Canada, then a British colony. American officials were overly optimistic about the invasion’s success, especially given how underprepared U.S. troops were at the time. On the other side, they faced a well-managed defense coordinated by Sir Isaac Brock, the British soldier and administrator in charge in Upper Canada (modern Ontario). On August 16, 1812, the United States suffered a humiliating defeat after Brock and Tecumseh’s forces chased those led by Michigan William Hull across the Canadian border, scaring Hull into surrendering Detroit without any shots fired.