The Mexican Army 's defeats at Palo Alto and Resaca de la Palma caused political turmoil in Mexico , turmoil which Antonio López de Santa Anna used to revive his political career and return from self-imposed exile in Cuba in mid-August 1846 . It was President Polk 's plan to bring back the exiled dictator who had defeated the Texans at the Alamo and Goliad . On 4 August 1846 , " Polk negotiated a deal to not only bring Santa Anna back , but to pay him $ 2 million — ostensibly a bribe as an advance payment on the cession of California . " Santa Anna promised the U.S. that if he was allowed to pass through the blockade , he would negotiate a peaceful conclusion to the war and sell the New Mexico and Alta California territories to the U.S . Once Santa Anna arrived in Mexico City , however , he reneged on his deal with the U.S. and offered his services to the Mexican government . Then , after being appointed commanding general , he reneged again and seized the presidency
Goliad
Goliad massacre
Mexican–American War