More notes: What’s the appeal of the Confederate prisoner to the Federal Posse? That is, what special knowledge or skill he brings to the hunt for the commander that the Feds can’t find among their own?

Also: a Federal posse has no legal authority to invade Mexico to capture the commander. So the posse would have to violate Mexican sovereignty — a dramatic complication, to be sure. In fact, going into Mexico illegally is a potentially more interesting dramatic hook to me than the fact that an ex-Confederate agrees to assist a Federal posse.