Why Putin is unveiling ‘invincible’ nuclear weapons now

Russian President Vladimir Putin boasted of new nuclear weapons that he says can defeat U.S. missile defenses in an address unveiling a grand vision for his country. His return to Cold War rhetoric comes a month after the U.S. announced its own plans to deploy new nuclear weapons and two weeks before the Russian election. Nick Schifrin talks with Richard Burt, former chief arms control negotiator.