Only because border control falls under the purview of DHS. If they did find something illegal, as far as I know all they could do is either deny her entry or h

Only because border control falls under the purview of DHS. If they did find something illegal, as far as I know all they could do is either deny her entry or hand her and the evidence they collected over to the FBI and see if the DOJ wants to bring charges. It definitely wouldn't be a matter for the military police - since she isn't a member of the military she isn't subject to the UCMJ. The only reason they would have done anything in Iraq would be because Poitras was in a war zone outside US territory. They, again, would have had to hand her over to the DOJ for prosecution.