The short-lived Republic of Texas survived for a time between Mexico and the expanding United States of America. The problem was that there were some disagreements with Mexico as to the exact nature of the Republic of Texas. Firstly, the ruler of Mexico had been captured when he signed the agreement that they were free. That was considered coercion, and the Mexicans had declared him no longer their ruler, elevated someone else, and did not recognize the entire agreement. Secondly, even if they did accept the agreement, they disagreed over the particulars. Texas said the agreement gave them all territory north of the Rio Grande River. Mexico said that they had a lot of towns full of Mexicans on the north side of the Rio Grand River, they weren’t giving them up, and if they DID accept a river border, it was a different river further north. But they still really didn’t. The disagreement turned violent when Texas patrols between the two rivers ran into Mexican patrols that did not want them there. As far as Texas was concerned, that meant war. As far as Mexico was concerned, it was another chance to shoot dirty rebels. As far the United States was concerned… well… who doesn’t love the story of plucky underdog rebels standing up to a vast empire trying to kill them? We Americans eat those stories for lunch.