Battle Cry of Freedom: The Civil War Era

by James M. McPherson

In return for a payment by the United States of $15 million plus the assumption of Mexican debts to American citizens, Mexico recognized the Rio Grande boundary of Texas and ceded New Mexico and upper California to the United States.6 When this Treaty of Guadalupe Hidalgo reached Washington in February 1848, Polk initially spurned it. On second thought, however, he submitted it to the Senate, where the Whigs would have enough votes to defeat any treaty that sliced off more Mexican territory but might approve one that avoided the appearance of conquest by paying Mexico for California and New Mexico. The strategy worked; the Senate ratified the treaty by a vote of 38-14, with five of the opposition votes coming from Democrats [Page 51] who wanted more territory and seven from Whigs who wanted none.7