US Presidency
1847

The commissioner of the United States was authorized to agree to the establishment of the Rio Grande as the boundary from its entrance into the Gulf to its intersection with the southern boundary of New Mexico, in north latitude about 32 degree, and to obtain a cession to the United States of the Provinces of New Mexico and the Californias and the privilege of the right of way across the Isthmus of Tehuantepec. The boundary of the Rio Grande and the cession to the United States of New Mexico and Upper California constituted an ultimatum which our commissioner was under no circumstances to yield.