From Paris to San Bernardino, terrorist attacks have sparked an outcry from many politicians in Europe and the U.S. - including calls for new controls on immigration, refugees and the free movement of labor across national borders.

The leading Republican Presidential candidate, Donald Trump, called for a total and complete ban on Muslims entering the United States.  

Our guest in episode 29, Peter Coy, Economics Editor for Bloomberg Businessweek, makes a strong case for more - not less - immigration, as well as a greater exchange of ideas across the boundaries that divide us.   

"One of the treasures of democracy is freedom of thought, freedom of action, freedom of movement," says Peter.  "In putting up walls we actually lose what we treasure the most."

The 28-state European Union has been a triumph for economic growth and a peaceful transition from the wreckage of World War 2. 

"You can drive from France into Switzerland without even pumping the brakes at the border," Peter told us. "This has been hugely beneficial to Europe, creating a single Europe with more trade, wealth and commerce than we would have."

Europe is the top destination for U.S. exports, but many economists see a big cost to the economy and to our culture from erecting new barriers in the name of safety.