USA HISTORY

Detailed explanation-1: -In 1843, U.S. President John Tyler, then unaligned with any political party, decided independently to pursue the annexation of Texas in a bid to gain a base of support for another four years in office.

Detailed explanation-2: -Polk accomplished this through the annexation of Texas in 1845, the negotiation of the Oregon Treaty with Great Britain in 1846, and the conclusion of the Mexican-American War in 1848, which ended with the signing and ratification of the Treaty of Guadalupe-Hidalgo in 1848.

Detailed explanation-3: -On December 29, 1845, Texas became the 28th state in the United States. Formerly part of Mexico, Texas had been an independent country since 1836. Since its independence, Texas had sought annexation by the U.S. However, the process took nearly 10 years due to political divisions over slavery.

Detailed explanation-4: -In 1844, Congress finally agreed to annex Texas. On December 29, 1845, Texas entered the United States as a slave state, broadening the irrepressible differences in the United States over the issue of slavery and setting off the Mexican-American War.