What man would not support the Confederate cause?

A notable case was General George Thomas.

When his home state of Virginia seceded, everyone expected him to resign his commission and join the Confederates.

But Thomas declared that he had sworn his oath to defend the United States, and that he would keep to his word. He went on to become one of the best generals in the Union, and the only one who totally routed a Confederate army, at the Battle of Nashville.

His family were so ashamed of his action that they turned his portraits to face the wall.