The Virginia in the Civil War Message Board

Irish in the Civil War

During the course of researching my husband's family name, we've discovered that his great grandfather, Patrick O'Day, was born in Ireland as per the 1860 census. We can find no record of him actually being in the military - although he was probably too old (1860 census says he was 45),,,, however we are curious as to his thoughts and those of other immigrants regarding the issues that brought about the Civil War. Does anyone know of any research or documentation of this issue?