<P> When Texas was annexed , Mexico broke diplomatic relations with the United States . The annexation bill did not specifically define the boundaries of Texas . The former republic claimed the Rio Grande as its southern border , while Mexican authorities had always considered the Nueces River , situated further north , to be the boundary of Mexican Texas . The United States sent John Slidell to negotiate with the Mexican government , offering $25 million ( $707,115,385 today ) to set the Texas border at the Rio Grande and to purchase Mexico 's provinces of Alta California and Santa Fe de Nuevo México . Popular sentiment in Mexico was against any sale , and the army deposed President José Joaquín de Herrera when he appeared inclined to negotiate with Slidell . </P>
<P> When Texas was annexed , Mexico broke diplomatic relations with the United States . The annexation bill did not specifically define the boundaries of Texas . The former republic claimed the Rio Grande as its southern border , while Mexican authorities had always considered the Nueces River , situated further north , to be the boundary of Mexican Texas . The United States sent John Slidell to negotiate with the Mexican government , offering $25 million ( $707,115,385 today ) to set the Texas border at the Rio Grande and to purchase Mexico 's provinces of Alta California and Santa Fe de Nuevo México . Popular sentiment in Mexico was against any sale , and the army deposed President José Joaquín de Herrera when he appeared inclined to negotiate with Slidell . </P>
river that mexico claimed was the texas border
river that mexico claimed was the texas border
the Nueces River
the Nueces River