Along the U.S.-Canada border, an invisible but hardening wall rises

https://www.washingtonpost.com/world/the_americas/along-the-us-canadian-border-frayed-ties-and-daily-hassles/2016/05/31/133230cc-241b-11e6-b944-52f7b1793dae_story.html?wpmm=1&wpisrc=nl_rainbow