From Boing Boing:
Under the Protecting Data at the Border Act, devices “belonging to or in the possession of a United States person” (a citizen or Green Card holder) could no longer be searched at the border without a warrant. Agents would no longer be able to deny US persons entry or exit on the basis of a refusal to allow such a search (but they could seize the equipment).
It doesn’t cover visitors or visa holders, but it does have bipartisan support in the Senate (Wyden D-OR; Paul R-KY) and the House (Polis D-CO; Farenthold R-TX).
The Customs and Border Protection agency conducted more warrantless device searches in Feb of 2017 than it did in all of 2015.