The Americans were angry with the British for many reasons.
But the United States was not really ready for war. The Americans hoped to get a jump on the British by conquering Canada in the campaigns of 1812 and 1813. Initial plans called for a three-pronged offensive: from Lake Champlain to Montreal; across the Niagara frontier; and into Upper Canada from Detroit.
The first American attacks were disjointed and failed. Detroit was surrendered to the British in August 1812. The Americans also lost the Battle of Queenston Heights in October. Nothing much happened along Lake Champlain and the American forces withdrew in late November.
In 1813, the Americans tried an intricate attack on Montreal by a combined land and sea operation. That failed.
One bright spot for the Americans was Oliver Hazard Perry's destruction of the British fleet on Lake Erie in September 1813 that forced the British to flee from Detroit. The British were overtaken in October defeated at the battle of the Thames by Americans led by William Henry Harrison, the future President It was here that the Shawnee chief, and British ally, Tecumseh fell.
Minor victories aside, things looked bleak for the Americans in 1814. The British were able to devote more men and ships to the American arena after having defeated Napoleon.
England conceived of a three-pronged attack focusing on controlling major waterways. Control of the Hudson River in New York would seal off New England; seizing New Orleans would seal up the Mississippi River and seriously disrupt the farmers and traders of the Midwest; and by attacking the Chesapeake Bay, the British hoped to threaten Washington, D.C. and put an end to the war and pressure the U.S. into ceding territory in a peace treaty.
All the while, support for the war waned in America. Associated costs skyrocketed. New England talked of succeeding from the Union. At the Hartford Convention, delegates proposed constitutional amendments that would limit the power of the executive branch of government.
So weak was American military opposition that the British sashayed into Washington D.C. after winning the Battle of Bladensburg and burned most of the public buildings including the White House. President Madison had to flee the city. His wife Dolley gathered invaluable national objects and escaped with them at the last minute. It was the nadir of the war.
But the Americans put up a strong opposition in Baltimore and the British were forced to pull back from that city. In the north, about 10,000 British army veterans advanced into the United States via Montreal: their goal was New York City. With American fortunes looking their bleakest, American Captain Thomas MacDonough won the naval battle of Lake Champlain destroying the British fleet. The British army, fearful of not being supplied by the British navy, retreated into Canada.
The War of 1812 came to an end largely because the British public had grown tired of the sacrifice and expense of their twenty-year war against France. Now that Napoleon was all but finally defeated, the minor war against the United States in North America lost popular support. Negotiations began in August 1814 and on Christmas Eve the Treaty of Ghent was signed in Belgium. The treaty called for the mutual restoration of territory based on pre-war boundaries and with the European war now over, the issue of American neutrality had no significance.
In effect, the treaty didn't change anything and hardly justified three years of war and the deep divide in American politics that it exacerbated.
Popular memory of the War of 1812 might have been quite so dour had it not been for a major victory won by American forces at New Orleans on January 8, 1815. Although the peace treaty had already been signed, news of it had not yet arrived on the battlefront where General Andrew Jackson led a decisive victory resulting in 700 British casualties versus only 13 American deaths. Of course, the Battle of New Orleans had no military or diplomatic significance, but it did allow Americans to swagger with the claim of a great win.Furthermore, the victory launched the public career of Andrew Jackson as a new kind of American leader totally different from those who had guided the nation through the Revolution and early republic. The Battle of New Orleans vaunted Jackson to heroic status and he became a symbol of the new American nation emerging in the early 19th century.