Why was there a strong debate surrounding the annexation of Texas

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