President Donald Trump declared a national emergency on the U.S. border in a bid to unlock money to build his wall. The constitutionality of the move was immediately challenged. Andrew Barden speaks to Anna Edgerton about how Trump hopes to build his wall, and how his opponents hope to tear the plans down. FOLLOW UPAnna's latest report: Trump Signs Spending Bill and Declares Emergency to Build WallYou can follow Anna at: @annaedge4----TicToc is a daily news podcast hosted by David Meyers (@davidfmeyers), produced at Bloomberg Worldwide HQ in New York City. You can follow up with us and watch our reporting @tictoc. If you like it, be sure to rate us on iTunes, and tell your friends!