Kammala wannan jumla: Bayan tashin hankali na farko, Taylor da yawancin sojojinsa sun yi tafiya daga kogin don tabbatar da layin samarwa, suna barin sansanin wucin gadi, Fort Texas. A kan hanyar dawowa zuwa Rio Grande, sojojin Mexico a karkashin Janar Mariano Arista sun yi kokarin toshe hanyar Taylor yayin da wasu sojojin suka kewaye Fort Texas, suna tilasta janar din sojojin Amurka ya kai hari idan yana fatan kwantar da hankalin sansanin. A cikin
Yaƙin Palo Alto, na farko da aka yi a yakin, sojojin Taylor sun tilasta Arista daga filin, suna shan wahala kawai hudu da suka mutu ga daruruwan Mexicans. Kashegari, Taylor ya jagoranci sojojin zuwa nasara a yakin Resaca de la Palma, ya sa sojojin Mexico su yi nasara. Nasarar farko ta karfafa goyon baya ga yakin, wanda duk da kuri'un da aka yi a majalisa ya raba kasa sosai. Yawancin Whigs na Arewa sun yi adawa da yaƙin, kamar yadda wasu suka yi; sun ji cewa Polk ya yi amfani da kishin ƙasa don yaudarar al'umma cikin yaƙin yaƙi wanda burin sa shi ne ya ba da damar bautar don faɗaɗa.