Ka kammala wannan magana: A watan Maris na shekara ta 1847, Polk ya ji cewa Taylor ya yi watsi da umurnin da aka ba shi kuma ya ci gaba da tafiya zuwa kudu, ya kama garin Saltillo da ke arewacin Mexico. Rundunar sojojin Taylor ta sake dawo da karfi na Mexico, wanda Santa Anna ya jagoranci, a cikin Fabrairu 1847 Battle of Buena Vista. Taylor ya sami yabo ga sakamakon yakin, amma wasan kwaikwayon ya kasance ba shi da kyau. Maimakon bin sojojin Santa Anna, Taylor ya koma Monterrey. A halin yanzu, Scott ya sauka a Veracruz da sauri
ya sami iko da birnin. Bayan kama Veracruz, Polk ya aika da Nicholas Trist, babban sakataren Buchanan, don yin shawarwari game da yarjejeniyar zaman lafiya tare da shugabannin Mexico. An umurci Trist da ya nemi rabuwa da Alta California, New Mexico, da Baja California, da amincewa da Rio Grande a matsayin iyakar kudancin Texas, da kuma samun damar Amurka a fadin Isthmus na Tehuantepec.