From the perspective of twenty-first-century America, it seems natural to assume that no other nation has ever been able seriously to threaten the continental states with its navy or military. The assumption that US geography has always deterred such pressure, however, ignores the early Victorian era. In the 1830s and 1840s, one nation could and did pose a credible threat to the United States: Great Britain. As the world’s supreme naval and financial power, Britain had the means to protect and advance its interests in the face of American belligerence. Ultimately, Britain’s strength deterred the United States from turning the tensions of 1838–46 into war. True, by this time Britain could never invade and reconquer its former American colonies. But it was never in its interest to go to war with the US. Anglo-American commercial relations were quite profitable, and peace kept them so. Furthermore, the British preferred a divided America, fighting over slavery and states’ rights, to one united against an external enemy. Britain’s goal was peace, but the methods it used to avoid war with the US in this period did not look particularly peaceful. Especially under Foreign Minister Lord Palmerston, preserving the peace did not equate with yielding in diplomatic battles. Rather, a ‘strong stance’ warned the US away from confrontations of a more lethal kind. Interestingly, the prospect of a British invasion through Canada played only a relatively small part in this deterrence. More important was the ability of the Royal Navy, with new gunnery and steam vessels, to strike at the populous and prosperous cities of the eastern and southern coasts of the US. Britain knew the possibilities for mayhem, as did the US government and some, at least, of the American public. Besides Britain’s technical advantages, its funding and political support for the navy were second to none. While the US struggled in vain to finance new ships and fortifications, the British cabinet could rest assured that if the Royal Navy required more funding, it would get it. The British government counted on the navy’s strength to intimidate the Americans in controversies over the Caroline and McLeod affairs, the Maine boundary and the Oregon territory. Palmerston’s personal style of ‘gunboat diplomacy’ may have encouraged this course, but he and his colleagues did worry that the political system of the United States might lead it to start a war neither side really wanted: the fevered American press and people might push the government to some act the British could not tolerate. Britain used the Royal Navy to signal the dire consequences of such an act and forced the American government to resist popular pressure. Geography in these cases was not enough to shield the US; Britain’s strong stance preserved its existing interests and maintained peace. [ABSTRACT FROM AUTHOR]