In January 1859, he was appointed as Superintendent at the federal armory in Harpers Ferry, Virginia (now West Virginia). He served there until the American Civil War began in 1861. In October 1859, abolitionist John Brown raided the arsenal. Brown's raiders captured the entire armory and town, which Brown knew to be minimally guarded by civilians, although ultimately he failed and was captured because he remained in town too long. Recent research questions whether Brown really attempted to steal the weapons to support a slave rebellion, considering that explanation Virginia slaveholder propaganda. Barbour wrote that he was visiting the federal armory at Springfield, Massachusetts. "Had I been here, I could have done no good. Old Brown would have taken Gen. Scott if he had been here. A military man could have done nothing more than a civilian, unless there had been a corps of soldiers under him. . . . It is ridiculous to talk about it, as if the presence of a military man [at Harper's Ferry] would have awed Old Brown."