Final answer:
Andrew Jackson was primarily concerned with maintaining the balance between free and slave states, which is why he did not pursue the annexation of Texas.
Step-by-step explanation:
Andrew Jackson did not seek to annex Texas mainly because he was concerned about upsetting the balance between free and slave states in the United States. This concern is reflected in the historical context of the era when the annexation of Texas was considered. The potential addition of Texas as a slave state would have disrupted the precarious balance in Congress between free and slave states, a sensitive issue following the Missouri Crisis. Moreover, there was the ongoing reality of conflicts with both Mexico and Native American tribes, such as the Comanches, which added to the complexity and potential for conflict inherent in annexing Texas.