My purpose and reasoning has nothing to do with current-day political debate. Aside from being inappropriate to a Civil War discussion board, I've have never seen a reference to the term 'Federal' as politically correct. If so, it's been that way for a long time. If you happen to have access to one of Bruce Catton's books on the Army of the Potomac, notice how many times he uses the word 'Federal'. Of course his publications all date from half a century ago.