act that they successfully realized in 1815. They were also keen to maintain what they saw as their rights to stop and search neutral vessels as part of their war with France, and further ensure that their own commercial interests were protected. Impressment, trade, and naval actions Britain was the largest trading partner of the United States, receiving 80 percent of American cotton and 50 percent of all other American exports. The British public and press resented the growing mercantile and commercial competition. Historian Reginald Horsman states that "a large section of influential British opinion [...] thought that the United States presented a threat to British maritime supremacy". During the Seven Years' War, Britain introduced rules governing trade with their enemies. The Rule of 1756, which the U.S. had temporarily agreed to when signing the Jay Treaty, stated that a neutral nation could not conduct trade with an enemy, if that trade was closed to them before hostilities had commenced. Since the beginning of Britain's war with France in 1793, the U.S. merchant marine had been making a fortune continuing trading with both nations, America's share of trans-Atlantic trade growing from 250 thousand tons in 1790 to 981 thousand tons in 1810, in the process. Of particular concern to the British was the transport of goods from the French West Indies to France, something the U.S. would have been unable to do, due to French rules, during times of peace. The United States' view was that the treaty they had signed violated their right to trade with others, and in order to circumvent the Rule of 1756, American ships would stop at a neutral port to unload and reload their cargo before continuing to France. These actions were challenged in the Essex case of 1805. In 1806, with parts of the Jay Treaty due to expire, a new agreement was sought. The Monroe–Pinkney Treaty offered the U.S. preferential trading rights and would have settled most its issues with Britain. However, the treaty did not moderate the Rule of 1756 and only offered to exercise "extreme caution" and "immediate and prompt redress" with regard to impressment of Americans. Jefferson, who had specifically asked for these two points to be extirpated, refused to put the treaty before the senate. In 1806, Napoleon's Berlin Decree declared a blockade of the British Isles, forbade neutral vessels harbour in British ports, and declared all British