When President Abraham Lincoln issued his call to arms in 1861, the 63rd, 69th and 88th New York Volunteers were among the first to step forward to defend the Union. Comprised primarily of first and second generation Irish immigrants, these three regiments were later joined by the 28th Massachusetts and the 116th Pennsylvania. Although many of these Irish men were decidedly anti-Lincoln--blaming the northern abolitionists as much as the southern rebels for the nation's plight--they worked around their dilemma by pledging their allegiance to their new country and its flag rather than its...