Barack Obama and Fidel Castro's Cuba

For the first time since 2006, American officials met yesterday with Fidel Castro in Cuba.  Members of the Congressional Black Caucus visited what they described as Castro’s “modest” house and reported that he was healthy and talkative as ever.  Democrat Barbara Lee of California said it’s time for a change. Even some Republicans want relations improved. They and other critics say US policy has been held hostage by Cuban-Americans in Florida, and has failed to get a repressive country to change its ways. Is it the US rather than Cuba that's being isolated from the rest of the world?  Can the President act without the approval of Congress, presuming he wants to?