On Friday, Arizona police arrested a 64-year-old man — a fugitive since 2001 in a bizarre war that mixes free speech, copyright law, and the Church of Scientology. Keith Henson’s journey began seven years ago while innocuously watching another critic mock the group on an internet newsgroup. In a gonzo discussion about procuring a "Tom Cruise missile," they’d joked about working with "Secret Agent 99, wearing a stunning black leather biker outfit." Other posters joined in the internet discussion, asking whether Tom Cruise missiles are affected by wind. "No way," Keith joked. "Modern weapons are accurate to a matter of...