<P> As president, however, Polk sought compromise and renewed the earlier offer to divide the territory in half along the 49th parallel, to the dismay of the most ardent advocates of manifest destiny . When the British refused the offer, American expansionists responded with slogans such as "The Whole of Oregon or None!" and "Fifty - Four Forty or Fight!", referring to the northern border of the region . (The latter slogan is often mistakenly described as having been a part of the 1844 presidential campaign .) When Polk moved to terminate the joint occupation agreement, the British finally agreed in early 1846 to divide the region along the 49th parallel, leaving the lower Columbia basin as part of the United States . The Oregon Treaty of 1846 formally settled the dispute; Polk's administration succeeded in selling the treaty to Congress because the United States was about to begin the Mexican--American War, and the president and others argued it would be foolish to also fight the British Empire . </P> <P> Despite the earlier clamor for "All Oregon", the Oregon Treaty was popular in the United States and was easily ratified by the Senate . The most fervent advocates of manifest destiny had not prevailed along the northern border because, according to Reginald Stuart, "the compass of manifest destiny pointed west and southwest, not north, despite the use of the term' continentalism"'. </P> <P> Manifest destiny played an important role in the expansion of Texas and American relationship with Mexico . In 1836, the Republic of Texas declared independence from Mexico and, after the Texas Revolution, sought to join the United States as a new state . This was an idealized process of expansion that had been advocated from Jefferson to O'Sullivan: newly democratic and independent states would request entry into the United States, rather than the United States extending its government over people who did not want it . The annexation of Texas was attacked by anti-slavery spokesmen because it would add another slave state to the Union . Presidents Andrew Jackson and Martin Van Buren declined Texas's offer to join the United States in part because the slavery issue threatened to divide the Democratic Party . </P> <P> Before the election of 1844, Whig candidate Henry Clay and the presumed Democratic candidate, former President Van Buren, both declared themselves opposed to the annexation of Texas, each hoping to keep the troublesome topic from becoming a campaign issue . This unexpectedly led to Van Buren being dropped by the Democrats in favor of Polk, who favored annexation . Polk tied the Texas annexation question with the Oregon dispute, thus providing a sort of regional compromise on expansion . (Expansionists in the North were more inclined to promote the occupation of Oregon, while Southern expansionists focused primarily on the annexation of Texas .) Although elected by a very slim margin, Polk proceeded as if his victory had been a mandate for expansion . </P>

What does westward expansion mean in us history