(Bloomberg) -- Corrects David Rivkin's name \u0010\u0010David Bier, an immigration policy analyst at the Cato Institute, and David Rivkin, a partner at Baker Hostetler, discuss a decision by the 4th U.S. Circuit Court of appeals to uphold a lower court ruling to block President Trump’s proposed travel ban. They speak with June Grasso and Greg Stohr on Bloomberg Radio’s "Bloomberg Law."