It is true that if he was in the war, he more than likely served for the Union. There is a book called Report of the Tennessee Adjutant General which contains rosters to the Union Regiments. Most large libraries will have one. Check each regiment for a William and james Smith. It will give the age they enlisted. Most likely they served together. Also check the 1890 Veterans census for a William or James receiving a pension (this is for Union pensions, but sometimes they slipped up and had a Confederate veteran listed). There are 21 William Smith's according to the Soldier's and Sailor's list, so you would have to do a process of elimination. According to the website Tennessee and the Civil War Virtual Cemetery there was no William Smith with a tombstone buried in Anderson County (I did not check james Smith) but not all soldiers tombstones are posted. Your names will indeed be a challenge, but it can be done; however, these are tips for you. Beulah Karr, Tennessee Civil War research and author of "One moment of Glory-A Tribute To Our Civil War Soldier's of Sevier County"