[New Republican Governor of Wisconsin] Scott Walker ordered the National Guard to get ready to respond to a strike or any resistance to his plan. The last time Wisconsin called in the National Guard during a labor dispute was way back in 1886, when Guard militiamen shot on a rally of Milwaukee workers advocating an 8-hour work day. Five unarmed workers were killed in the massacre.
From a good post: Class Warfare in Wisconsin: 10 Things You Should Know
UPDATE: The tumblr hardcorefornerds reblog’d this post and has some nice additional reporting on if the statement “The last time WI called in the National Guard during a labor dispute was way back in 1886…” is actually correct. The incident did happen (sourced in the post the quote above was from), however it does not appear that was “the last time” the National Guard had been summoned during a labor dispute. Read hardcorefornerds’ post for details. Nicely done.