Rubuta ci gaba ga wannan sakin layi - A watan Mayu 1846, Buckner ya yi murabus daga matsayinsa na koyarwa don yin yaƙi a cikin Yakin Mexico-Amurka, ya shiga tare da Rundunar Sojojin Amurka ta 6. Ayyukansa na farko sun hada da tattara sojoji da kuma kawo su zuwa iyakar Texas. A watan Nuwambar 1846, an umurce shi da ya shiga kamfaninsa a filin; ya sadu da su a hanya tsakanin Monclova da Parras. Kamfanin ya shiga John E. Wool a Saltillo. A cikin Janairu 1847, an umurci Buckner zuwa Vera Cruz tare da rabon William J. Worth. Yayin da Manjo Janar Winfield Scott ya kewaye Vera Cruz
, Buckner ta naúrar tsunduma 'yan dubu Mexican sojan doki a kusa da garin da ake kira Amazoque.