One of [President John] Tyler’s final acts as president was one of his most monumental. Whereas in 1842 the Senate had ratified the Webster-Ashburn Treaty, which settled many boundary disputes between Canada and the United States, senators split over the legality and ramifications of annexing Texas. By the time, the annexation question reached the White House, the secretary of state was John Calhoun, who had returned to the position he had held under President Monroe. Calhoun believed Texas would become a proslavery state and thus tip the balance of power in the Senate in favor of the interests of slaveholders. He believed that treaty between the United States and Texas, which saw itself as a small nation, was lawful; however, many Democrats and Whigs were concerned that Mexico would invade Texas if there were such a treaty. Many Democrats also wanted the next president to handle the matter. Whigs did not want a war, but they opposed acquiring a territory that would become a slave state and happily opposed Tyler and Calhoun whenever possible.
In spite of the skepticism and threatened opposition, Calhoun and Tyler negotiated a treaty with Texas on April 12, 1844, which they sent to the Senate ten days later. Along with the treaty, they sent supporting documentation, including a letter from Tyler emphasizing that the treaty was in the best interests of everyone and that the federal government had the power to execute the treaty pursuant to its authority to acquire new territories and to admit new states. It was soon discovered that the documentation included two letters that Calhoun had written to Richard Pakenham, the British minister in Washington, D.C. In both letters, Calhoun explained that the treaty was needed to protect slavery in the United States. Although the chances of ratification were uncertain before the two letters were released, they disposed all senators, except for those most committed to Calhoun, to reject the treaty’s ratification.
The Senate debated the treaty for nearly a month. Several prominent Democrats favored treaty ratification, while the Whigs opposed it. Clay was pleased the Senate fell ten votes shy of the two-thirds required for treaty ratification.
Tyler did not quit. After consulting with Calhoun, he proposed an alternative to treaty ratification. He suggested that a simple majority in each chamber of Congress could approve the agreement with Texas. This was the same procedure required for acquiring territory or admitting a new state as provided by implication in Article IV. Just two days after the Senate rejected the treaty, Tyler sent a copy of the agreement to the House with a message declaring that it had the authority to approve the agreement pursuant to the powers granted in
Article IV to admit new states into the Union.
Construing Polk’s victory in the 1844 presidential election as a mandate for annexation, Tyler pressed Congress to approve the agreement. Just a few days before Polk’s inauguration, the House and Senate each approved a resolution giving the president the choice of annexing Texas according to the resolution that the House had approved or by opening new negotiations with Texas as specified in a resolution from Missouri senator Benton. On March 1, Tyler signed the joint resolution. Shortly after his inauguration, President Polk chose not to challenge the authority of the joint resolution or Tyler’s signature.
– Forgotten Presidents Their Untold Constitutional Legacy by Michael J. Gerhardt