a new era of peace between the two nations. Disputes 1815–60 The Monroe Doctrine, a unilateral response in 1823 to a British suggestion of a joint declaration, expressed American hostility to further European encroachment in the Western hemisphere. Nevertheless, the United States benefited from the common outlook in British policy and its enforcement by the Royal Navy. In the 1840s several states defaulted on bonds owned by British investors. London bankers avoided state bonds afterwards, but invested heavily in American railroad bonds. In several episodes the American general Winfield Scott proved a sagacious diplomat by tamping down emotions and reaching acceptable compromises. Scott handled the Caroline affair in 1837. Rebels from British North America (now Ontario) fled to New York and used a small American ship called the Caroline to smuggle supplies into Canada after their rebellion was suppressed. In late 1837, Canadian militia crossed the border into the US and burned the ship, leading to diplomatic protests, a flare-up of Anglophobia, and other incidents. Tensions on the vague Maine–New Brunswick boundary involved rival teams of lumberjacks in the bloodless Aroostook War of 1839. There was no shooting but both sides tried to uphold national honor and gain a few more miles of timber land. Each side had an old secret map that apparently showed the other side had the better legal case, so compromise was easily reached in the Webster–Ashburton Treaty of 1842, which settled the border in Maine and Minnesota. In 1859, the bloodless Pig War determined the position of the border in relation to the San Juan Islands and Gulf Islands. British leaders were constantly annoyed from the 1840s to the 1860s by what they saw as Washington's pandering to the democratic mob, as in the Oregon boundary dispute in 1844–46. However British middle-class public opinion sensed a "special relationship" between the two peoples based on language, migration, evangelical Protestantism, liberal traditions, and extensive trade. This constituency rejected war, forcing London to appease the Americans. During the Trent affair of late 1861, London drew the line and Washington retreated. In 1844-48 the two nations had overlapping claims to Oregon. The area was largely unsettled, making it easy to end the crisis in 1848 by a compromise that split the region evenly, with British Columbia to Great Britain, and Washington, Idaho, and Oregon to America. The US then turned its attention to Mexico, which threatened war over the