Abraham Lincoln
The Texas Constitution forbade it.
The first president of the Republic of Texas under the Texas Constitution of 1836 was Sam Houston. He served from 1836 to 1838 and played a crucial role in leading Texas to independence from Mexico. Houston's leadership during the Texas Revolution and his subsequent presidency helped shape the early years of the Republic.
The constitution of Texas!
Because the Texas Constitution did not allow it.
Sam Houston was never US President, but he was the first and third president of the Republic of Texas, US Senator when Texas joined the US, and ultimately Governor of Texas. He did not serve consecutive terms as president, because the Constitution of the Republic of Texas prohibited that.
US President Lincoln often tried to guide the Union's military forces. He believed that an invasion of Texas would galvanize New England support for the war. If the Union could control Texas its vast supplies of cotton could be shipped to New England's textile mills. Lincoln appointed the governor of Massachusetts, Nathaniel P. Banks to raise an expeditionary force to assault Texas from the Gulf of Mexico. Later Lincoln changed the destination of Bank's forces to southern Mississippi. The reason was for the control of the Mississippi River.
How did the new Texas Constitution treat Mexicans living in Texas?
I suspect you mean 1836, not 1863, since the last President of Texas left office in February of 1846, after Texas became a state of the United States. David G. Burnet was elected Interim President in 1836 by the convention that assembled to issue Texas' Declaration of Independence from Mexico. Later that year Sam Houston was elected by popular vote to be the first President of Texas. He was also the third President of Texas (the Texas Constitution did not have term limits, but it did not allow anyone to serve consecutive, or back to back, terms).
The 1836 Texas Constitution established Texas as an independent republic following its separation from Mexico. It created a framework for government, including a separation of powers among the executive, legislative, and judicial branches, and affirmed individual rights such as freedom of religion and trial by jury. The constitution also facilitated the election of a president and a legislature, setting the stage for the establishment of a functioning democratic government in the newly formed Republic of Texas.
John Tyler in one his last official acts signed the bill proposing that the United States annex Texas . In December of 1845 when the annexation was supposed to begin, Texas became a state, having drawn up a constitution and asking for statehood. James K. Polk was the President at that time.
The Texas Constitution of 1836 established the Republic of Texas and granted broad powers to the president. The Constitution of 1845 admitted Texas as a state, but maintained many provisions from the 1836 constitution, including the strong executive branch. The Constitution of 1876, in response to concerns of centralized power, sought to limit the authority of the governor and return power to smaller governments, such as county governments. It also included provisions aimed at limiting state debt and land grants.