Bob, I agree with you on the soldier explanation for the chorus lyric -- that just makes sense to me. I wonder if another graft produced the version I know: an outlaw song with a soldier song. I know it's a fraught exercise to deduce the time period of a traditional song from its lyrics, but it's tempting in this case to read about the cops "riding after" our protagonist and imagine a mounted posse.

The definitions of "deadhead" that Gargoyle posted above on 7/10/03 are all 19th century vintage. Perhaps the song predates WWI... Since both deadhead and sucker were in use by the 1860s, it might even be of Civil War provenance.

There is another definition of "sucker" that hasn't been mentioned: a con artist's mark, a victim of a scam, as in "There's a sucker born every minute."

Jerry