Obama admin probably had something to do with this. Why would the union be opposed as illegal alien workers take jobs away from union shops
and drive wages down.
I'd bet on it. The local Border Patrol always seems eager to tell their story and voice their complaints at not being allowed to do their job. This probably came from DHS under Obama's orders.
I wonder what justification there could be. All sorts of people frequently tour the border and I've never heard the of the BP being ordered to not cooperate with a high profile figure before.
Hopefully some reporters will dig into this and see if there are any precedents or justifications other than politics.