A printed list of the 152 delegates elected to the Virginia Convention of 1861 includes John S. Carlile from Harrison County. He was one of two representatives from that county (the other was Benjamin Wilson) to attend the convention in Richmond that was dedicated to formulating an official Virginia response to the secession crisis. The proceedings lasted from February 13 until May 1, 1861.
Throughout the convention, Carlile spoke passionately in favor of the Union and against secession, which he denounced as the product of a Southern conspiracy, as "self murder," and as "an insult to all reasonable living humanity, and a crime against God." Emphasizing that he was a slave-owner by purchase and not by mere inheritance (at that time he may have owned only one slave) and consequently was not to be confused with Republicans or abolitionists, he argued that Virginia slavery would be more secure if the state remained in the Union. One of the acknowledged leaders of western Virginia's Unionists, Carlile was the target of secessionist criticism. He was once assaulted and on another occasion observed a crowd outside his boardinghouse brandishing a rope and threatening to hang him. He voted against secession when the motion failed on April 4, 1861, and again when it passed on April 17.
Other prominent members of the convention included Henry A. Wise, delegate from Princess Anne, who had been governor during the 1859 assault on Harpers Ferry by the abolitionist John Brown. Wise became the most vocal champion for secession. Taking an opposing view of the issue was Franklin County Unionist Jubal A. Early, who would later win fame as a Confederate general during the Civil War. John Quicy Marr from Fauquier County straddled the fence during the proceedings, voting first against secession on April 4, and then in favor of it during the final vote on April 17. A month and a half later, on June 1, 1861, the 36-year-old Marr was killed at Fairfax Courthouse and became the first Confederate officer to die during the war.