The Republic of Texas was created in March 1836 and existed as a sovereign nation until February 1846, although Mexico did not recognize it as such. During this time, many people in Texas actively agitated for American annexation. Both the Jackson and Van Buren administrations were leery of addressing the issue directly, fearing increased political division by expanding slavery through annexation. John Tyler argued that annexation would benefit the nation economically. However, Tyler’s autocratic leadership style failed to achieve annexation. In 1844 James Polk, an ardent supporter of slavery, was elected to the presidency largely based on his promise to expand the borders of the United States into Oregon and Texas, either diplomatically or through force. Polk had achieved his aims diplomatically in the Oregon territory. This won him a great deal of popular support for championing both the Monroe Doctrine and the ideal of manifest destiny. Meanwhile, Texans had voted for annexation, and Polk officially recognized Texas as the twenty-eighth state in December 1845, with the transfer occurring two months later.