In 1836, the Republic of Texas voted to be annexed by the US. Initially, when the Texas minister in Washington, D.C., proposed annexation to the administration of Martin Van Buren in August 1837, the request was refused since the administration was afraid of wars with Mexico and Texas withdrew the annexation offer in 1838. In 1843, Britain opposed annexation, and President John Tyler, who did not want to do anything to help Britain, proposed annexation. Despite the fact that Mexican leader Antonio López de Santa Anna warned that annexation would be "equivalent to a declaration of war against the Mexican Republic," John Tyler signed a treaty of annexation with Texas in April 1844. Sam Houston consented to the proposed annexation. A factor, always in the background, during the Texas Annexation discussions in the United States was the fear of the north that the slave states would gain representation when Texas was admitted as a slave state.
After James Polk, a strong supporter of territorial expansion, won the presidency, but before he took office, Congress approved the annexation on 28 February1845. On 29 December1845, Texas ceased being an independent nation and now has representation as a state as defined by the U.S. Constitution.
Both the Joint Resolution for Annexing Texas and The Ordinance of Annexation contains this language providing the basis for forming up to four additional states from the present Texas:
New States of convenient size not exceeding four in number, in addition to said State of Texas and having sufficient population, may, hereafter by the consent of said State, be formed out of the territory thereof, which shall be entitled to admission under the provisions of the Federal Constitution.
Texas first popularly elected President, Sam Houston, the victor of San Jacinto, had in his Tennessee youth been a protégé of Andrew Jackson, who in 1836 was closing down his eight-year tenure in the White House.
Compromising none of its independent posture, Texas negotiated a treaty that provided for the United States to take possession of her debts and her public domain, and admit her as a territory, with individual states to be excised and admitted as they qualified for admission.
Texas retention of her public domain allowed her to stake thousands of small homesteaders with pre-emption grants, construct a web of internal improvements (largely railroads), build the largest of all state capitols, fund public schools, and endow a state university system.
Texas was becoming so prosperous its capacity for self government established---its foreign relations so friendly and advantageous---peace with Mexico in prospect with certainty of speedy accomplishment they who had before spurned Texas might now well fear that the next refusal would come from this side of the Sabine, and the refusal would be final.
In Texas at that day when the masses of the people were as intelligent, as high toned, as zealous, as patriotic as gentlemen of the class commonly considered leaders of public opinion, it was a matter of course that the falsehoods and suspicions adverted to should tell on the masses of our people.
When the decision of the people was clear for annexation and its accomplishment a foregone conclusion, he squrely took ground in its favor and voted for it, on the avowed reason that in an irreversible act he would not in sentiment be separated from his own people.