William Selby Harney (American National Biography)

In June 1846, as the nation moved toward war with Mexico, Harney became colonel and commander of the Second Dragoons. When hostilities began, the headstrong commander conducted an unauthorized expedition into Mexico from Texas, and General Winfield Scott ordered Harney to surrender most of his command to a subordinate. Harney subsequently defied Scott by retaking command. Scott then ordered a court-martial, which convicted Harney of disobedience and ordered him to apologize to Scott. After the trial, however, Harney retaliated by using political channels to obtain a reprimand against Scott from Secretary of War W. L. Marcy.

Harney served with distinction during the march to Mexico City. He captured Cerro Gordo, a hill overlooking the road to Mexico City, and turned Mexican guns on the retreating enemy. During the siege of Mexico City, he busied himself by guarding prisoners and hanging American deserters.