The second post in our series on the interesting background of the Mexican War is on Oregon.
While Mexico held the desirable land of Upper California, it was Great Britain which provoked the first conflict with the U.S. on the Pacific Coast, and Oregon that was the disputed territory.
Today’s States of Washington and Oregon were, in 1846, a disputed area that Britain called the Columbia District and the U.S. called the Oregon Territory. By 1840, British citizens and officials in Canada began to petition London to annex the Columbia District—the disputed zone—and make it a part of the British Empire, an extension of British Canada. It was in part expanded American settlement in the disputed zone—what the settlers called Oregon Territory—that led the British to call for annexation.
Unfortunately for those advocates of British expansion, a new government in London led by Prime Minister Robert Peel came to power in 1841 which advocated strengthening Britain’s home defenses and home industry rather than further colonial expansion. While Britain was not actively working, then, to annex the disputed zone, Americans did not know this, and in 1844 the Democratic party began to insist that the U.S. not only officially incorporate the Oregon Territory, but also British Canada up to the border with Russian Alaska—the border at latitude 54°40′.
The Oregon Dispute was on. James Polk became president in 1844 and began negotiations with Great Britain for a U.S. annexation of the disputed zone up to the 49th parallel—the modern-day borderline between Washington State and Canada. But Democratic politicians, led by an Indiana Senator and a Missouri Congressman, called for the U.S. to annex British Canada up to 54°40′, and the catchphrase “Fifty-four Forty or Fight!” was born.
Of course, while there were always a few Manifest Destiny hotheads calling for war in the west in this period, neither nation really wanted to fight another war. The U.S. and Britain had been in conflict over western land on the North American continent since 1763, when the French and Indian War ended and the British forbid American settlers to move west of the Appalachians. Now, after the Revolution and the War of 1812, both sides wanted a diplomatic answer to the conflict over the disputed zone.
They got one, in the 1846 Oregon Treaty, which set the current border between the U.S. and British Columbia, Canada. But why did the conflict fizzle out so quickly? And why is this post about Canada and the Pacific Northwest in our series on the Mexican War?
The answer is that at the same time it was negotiating with Britain over the disputed zone, the U.S. was teetering on the brink of war with Mexico over Texas. Texas, the territory that most Americans would have traded in a heartbeat for Upper California, had been admitted into the Union as a state in 1845, despite the fact that it had never been officially given its independence by Mexico. Mexico broke off diplomatic relations with the U.S. and prepared for war. The U.S. needed a victory in Texas to pave the way for a smooth annexation of Upper California; Mexico had to be defeated by and in fear of the U.S. to make that possible. So war over Texas it must be, and matters in the Pacific Northwest had to be wrapped up. It was also key to have firm and official U.S. control of the lands bordering Upper California, so that Mexico would be surrounded by U.S. territory, and could be invaded if necessary from the north.
The Historic Present 