Our Navy and Coast Guard are already nearby and Congress is pushing legislation to aid dissidents in Cuba with money. All just in case Castro dies.
When Castro dies--or if he is already, when it becomes known--we could see a lot of refugees rolling into Florida. Plus Cuban exiles might be tempted to go to Cuba to take part in a civil war if that develops.
And if civil war or even just factional jockeying for position occurs, might not Chavez of Venezuela be tempted to intervene to keep Cuba in the Axis of El Vil?
The world moves on though we have other priorities. Iran may get a massive distraction to put off the day of reckoning over the mullahs' nuclear weapons programs.
If chaos breaks out in Cuba , it may be wise to blockade the island to keep out any foreign personnel who might take sides--either exiles or Venezuelans. And quietly encourage the opposition. I'm tempted to say that Cubans would resent American interference after decades of Castro propaganda, but proximity to us and contact with exiles may have kept Cubans in general from having a poor opinion of America. And prevented Cubans from thinking they live in a worker's paradise.
Best to keep an eye on this brewing crisis.