David, from the limited number of letters and diaries I've read, which were written by Southerners who joined the Union army, a common theme seems to be a relatively more evolved sense of nation and citizenship. Many of these Southerners wrote movingly about their unwillingness to abandon the Stars and Stripes. Few, if any, that I recall wrote anything about slavery, or even the right of secession. They just seemed to have a strong loyalty to the United States. Robert E. Lee expressed this same sentiment, and he had to dig deep into his soul to come to his decision to throw his lot in with Virginia. Straddling the fence was not an option. A man had to go one way or the other.