 The State of Vermont asked for Warner's services to lead a volunteer regiment, which was agreed to, and he was appointed colonel on September 1, 1862, and assigned to command the 11th Vermont Infantry (also known as the 1st Artillery, Vermont Volunteers).His regiment was assigned to the northern defenses of Washington, D.C., from September 1862 until May 1864, when Lt. Gen. Ulysses S. Grant called for more troops to support his Overland Campaign.The 11th Vermont joined the Vermont Brigade after the Battle of the Wilderness, and first saw action at the Battle of Spotsylvania Court House.