President Obama is expected to meet Cuban President Raul Castro in Panama at the Summit of the Americas. There's a good chance the State Department will soon remove Cuba from its state sponsors of terrorism and discuss plans to re-open embassies in D.C. and Havana.
Let me offer a prediction. The next time Obama and Castro meet it will be at the White House. I believe President Obama will invite both Raul and Fidel Castro to visit the United States before the end of his term. Fidel is probably not well enough to travel, but I expect him to extend the invitation anyway. In turn, the Castros will invite Obama to visit Cuba.
And if that happens then look for Marco Rubio to eviscerate both the Obama Administration and Rand Paul, who is supportive of Obama's Cuba engagement policy.