The Military is not doing any direct law enforcement in their support to DHS.
They are back-filling badged Border Patrol Officers from other duties, so those with legal arrest powers can be used where needed.
They also perform some other functions, like operating their own surveillance systems to watch the border, or hardening the border infrastructure (welders installing crowd control barriers at Ports of Entry, and Combat Engineers emplacing concertina on the bollard barriers).
None of the Military support is to confront banditos directly.
. ...well, I just seem to recall some National Guard troops getting held at gunpoint by Mexican Soldiers one or two months back?????
I have no problem with that
If our military is doing support for border patrol, so more border patrol can be out there arresting/detaining, that is fine with me.
I have no problem with our military doing back end support, infrastructure work/repairs etc