The Baltimore Plot: What was Pinkerton Thinking?

[RJNorton]

For some reason I have always had problems getting a grasp on the Baltimore Plot. I think part of this feeling is due to the fact that some experts have questioned its existence. For example, Harold Holzer writes, "If a Baltimore Plot existed at all, it was at most ad hoc, poorly organized and probably destined to fail." If he were right I would think prosecution of those involved might have been challenging.