Unless I missed something, nobody's mentioned one important factor in this. The Cuba embargo is a fly in the ointment of free trade doctrine, which ointment lubricates the penetration of the periphery by the center. Go ahead and make up your own joke. I believe this will come to have legal ramifications, if it hasn't already.
The U.S. needs to normalize relations with Cuba to facilitate the takeover of the world economy by the IMF/WTO/WB. There is also the narrower matter of business interests who would profit from a lifting of the embargo. This doesn't mean it isn't the right thing to do, only that the context is as interesting as the issue.
We are at the point where Capital is not sufficiently afraid of Cuban socialism to forego the profits that would come from opening up to Cuba.
mbs