Like other border states, Maryland found herself in a difficult position at the start of the American Civil War, with loyalties divided between North and South.
Many militia members travelled south at the start of the war, crossing the Potomac River to join the Confederate Army of Northern Virginia.
In 1859 units of the Maryland Militia participated in the suppression of John Brown's raid on Harpers Ferry, an abortive attempt to ignite a slave rebellion.
In a letter to his father, the younger Steuart wrote: I found nothing but disgust in my observations along the route and in the place I came to – a large majority of the population are insane on the one idea of loyalty to the Union and the legislature is so diminished and unreliable that I rejoiced to hear that they intended to adjourn...it seems that we are doomed to be trodden on by these troops who have taken military possession of our State, and seem determined to commit all the outrages of an invading army.
Steuart moved south for the duration of the American Civil War, and much of the general's property was confiscated by the Federal Government as a consequence.