Wich issue lead to texas seceding from the union

The issue of slavery lead to the Texas seceding from the union.

Explanation:

After Abraham Lincoln got elected as the President of the United States, the Governor of Texas, Sam Houston, found himself under tremendous public pressure and decided to secede from the union as a majority cotton-growing and slave-holding farmers started fearing the possible actions of Abraham Lincoln against slavery.

The ordinance of the secession was passed with 166 votes against 8 in the convention and thus, the state of Texas seceded.

The convention adopted an "Ordinance of Secession" by a vote of 166 to 8, which was ratified by a popular referendum on February 23 ... - Texas Secession Convention, A Declaration of the Causes which Impel the State of Texas to Secede from the Federal Union,