By 1812, Great Britain had been at war with Napoleonic France for nine long years. Both sides in the conflict had their enthusiastic partisans among America's political elite; Republicans such as Jefferson supported France, whereas Federalists tended to favor closer ties with Britain. After Jefferson became President in 1801, relations between the United States and Britain deteriorated sharply. At the heart of the growing animosity between the two countries was the thorny issue of trade. Great Britain used its superiority as a maritime power to enforce a naval blockade against France to ensure that the enemy would be starved of essential goods. This enraged the Jefferson Administration, which realized the enormous damage that the blockade would do to American trade.
Moreover, the British impressed—that is to say, forced—American merchant seamen into the Royal Navy to man the blockade. In other words, American citizens were being forced against their will to carry out a policy that most Americans did not believe was in their country's best interests. The British further inflamed matters by supplying arms to Native American tribes, who proceeded to conduct raids on white frontier settlements. It seemed to many Americans that the British were trying to halt the United States' territorial expansion. Under the circumstances, it was almost inevitable that war would break out sooner or later.