> You can't write an executive order that says you can get access to something you previously needed a warrant for without a warrant.
Well, you can. If the US AG thinks it's illegal, you can fire her. If it's argued in court, you've got a floating SCOTUS appointment ready to make.
(The distinction between "can they do that?" and "can they legally do that?" is normally pedantic but at a time when CBP are reported to be ignoring court orders ( http://nypost.com/2017/01/29/customs-agents-ignore-judge-enf... ), this is becoming increasingly important)
