First steps
Declaration of War — Baltimore Riots
The United States declared war on June 18, 1812, with the Twelfth Congress passing the measure on a nearly party-line vote. Word of the declaration reached Britain at the end of July, as the British ambassador returned home with the news and with new peace terms offered by President Madison. Though Britain had already repealed the Orders-in-Council that restricted trade with the Continent, the two nations could not find common ground on the issue of impressment. On October 13, 1812, the British government issued another Order-in-Council enabling British forces to enter into the conflict.
Opposition to the war did not end upon its official declaration. Though war hawks unsuccessfully promoted a sedition act to quash criticism of the war, Federalists in New England and elsewhere continued to speak out, discussing possible action in legislatures and other groups. Where those opposed to the war were in the minority, mobs sometimes sought to silence criticism through violence. Notorious riots in Baltimore targeted a Federalist newspaper publisher, persisting for six weeks and resulting in burned buildings and a number of deaths.
Military action in the War of 1812 occurred in several theaters. The borderlands between Canada and the United States were the most important area of conflict. It was not that the acquisition of Canada was a top military goal, but British North America was the closest place to strike at Britain. Fighting centered on and around Lake Ontario and Lake Erie, both in Upper and Lower Canada, and in the Old Northwest, consisting of Ohio and the Michigan and Indiana Territories. Later in the war, significant fighting took place in the Chesapeake Bay area and in the south.