<P> The Embargo Act had no effect on Great Britain and France and was replaced by the Non-Intercourse Act of 1809, which lifted all embargoes on American shipping except for those bound for British or French ports . As this proved to be unenforceable, the Non-Intercourse Act was replaced in 1810 by Macon's Bill Number 2 . This lifted all embargoes but offered that if either France or Great Britain were to cease their interference with American shipping, the United States would reinstate an embargo on the other nation . Napoleon, seeing an opportunity to make trouble for Great Britain, promised to leave American ships alone, and the United States reinstated the embargo with Great Britain and moved closer to declaring war . </P> <P> Exacerbating the situation, Sauk Indians who controlled trade on the Upper Mississippi were displeased with the U.S. Government after the 1804 treaty between Quashquame and William Henry Harrison . This treaty ceded Sauk territory in Illinois and Missouri to the U.S.; the Sauk felt this treaty was unjust, that Quashquame was unauthorized to sign away land, and that he was unaware of what he was signing . The establishment of Fort Madison in 1808 on the Mississippi further aggravated the Sauk, and led many, including Black Hawk, to side with the British before the war broke out . Sauk and allied Indians, including the Ho - Chunk (Winnebago), were very effective fighters for the British on the Mississippi, helping to defeat Fort Madison and Fort McKay in Prairie du Chien . </P> <P> Oxford historian Paul Langford looks at the decisions by the British government in 1812: </P> <Dl> <Dd> The British ambassador in Washington (Erskine) brought affairs almost to an accommodation, and was ultimately disappointed not by American intransigence but by one of the outstanding diplomatic blunders made by a Foreign Secretary . It was Canning who, in his most irresponsible manner and apparently out of sheer dislike of everything American, recalled the ambassador Erskine and wrecked the negotiations, a piece of most gratuitous folly . As a result, the possibility of a new embarrassment for Napoleon turned into the certainty of a much more serious one for his enemy . Though the British cabinet eventually made the necessary concessions on the score of the Orders - in - Council, in response to the pressures of industrial lobbying at home, its action came too late.... The loss of the North American markets could have been a decisive blow . As it was by the time the United States declared war, the Continental System (of Napoleon) was beginning to crack, and the danger correspondingly diminishing . Even so, the war, inconclusive though it proved in a military sense, was an irksome and expensive embarrassment which British statesman could have done much more to avert . </Dd> </Dl>

What is the most common reason given for america's declaration of war on britain in 1812