When Texas split from Mexico in 1836, its citizens were largely in favor
of annexation by the US. Most of US political leaders, however,
were against it. One main issue was that Texas practiced slavery.
Political leaders feared that dealing with Texas's slavery would stir up
even greater controversy. Perhaps an even greater concern, though, was
that Mexico was not happy about the loss of Texas. US political leaders
feared the war that the annexation of Texas would no doubt spark
It made getting from New York to the Pacific ocean easier and faster and getting from San Francisco to the Atlantic ocean easier and faster. Hope this helps!