The president of Poland, Andrzej Duda, has repeated his call for the US to base nuclear weapons on Polish soil. In the presidential palace in Warsaw, he told me that it would make Poland stronger and safer, as it faces Russia. Viewed from Poland, President Putin's Russia is a clear and a present danger.

Polish President Andrzej Duda has called on the U.S. to move some of its nuclear arsenal to Polish territory to deter potential future Russian aggression. Why it matters: The move would likely anger Moscow,