Cuba's biggest threat to U.S. is collapse, says former defense secretary

As President Trump makes threats against Cuba, former Defense Secretary Robert Gates said the biggest risk the Communist-ruled island poses to the U.S. is its potential collapse and a migration crisis to the U.S. "The biggest risk is that we end up with another Mariel evacuation from Cuba that has tens of thousands of Cubans heading to the United States out of desperation," Gates said Friday in an interview with "Face the Nation with Margaret Brennan." Known as the Mariel Boatlift, about …