* Economic interests: Southerners saw Texas as a potential market for their goods and services. Texas was also a large and fertile state, which meant that it had the potential to become a major cotton-producing region. This would have benefited Southern plantation owners, who were heavily dependent on cotton for their livelihoods.
* Political power: The annexation of Texas would have increased the political power of the South in the United States. This was because Texas would have been admitted to the Union as a slave state, which would have given the South more votes in the Senate and the House of Representatives. This would have made it more difficult for the North to pass legislation that was opposed by the South.
* Cultural affinity: Southerners felt a cultural affinity with Texans. Both groups were largely agricultural societies, and they shared many of the same values and traditions. This made it easy for Southerners to identify with Texans and support their desire for annexation.
Of course, there were also some Southerners who opposed the annexation of Texas. These critics argued that Texas was too large and too distant to be effectively governed by the United States. They also feared that the annexation of Texas would lead to war with Mexico. However, these concerns were outweighed by the economic, political, and cultural benefits that Texas offered to the South.
In the end, the vast majority of Southerners supported the annexation of Texas. This support was instrumental in getting Texas admitted to the Union in 1845.