I've been reading LeoGrande and Kornbluh's Back Channel to Cuba, which I will review once I'm done. As I read, I am struck by how much U.S. policy is on a treadmill, where we claim to be moving forward even though we're not.
In 1975, as the Ford administration--under Henry Kissinger's direction--prepared for some sort of normalization of relations, Harry Shlaudeman wrote a memo outlining the situation. It's declassified here at the National Security Archive.
Castro now has no apparent reason to concern himself further about the OAS sanctions. In fact, he has already succeeded in breaking the inter-American "blockade" without making a single significant concession and without ever having to deal with us. He may believe that a little patience will bring him the same happy result with respect to the U.S. sanctions...In brief, from where he sits, and from what he can see of the course of U.S. politics, there is not much to negotiate about.
Fast forward forty years--after the Cuban Democracy Act, Helms-Burton, changes in travel and remittances, agreements on immigration, etc, etc.--and this remains true. The United States has no leverage over Cuba. The status quo works quite well for the Castro regime, and it feels no need to make concessions.
Right after this memo was written, Fidel Castro sent troops to Angola and U.S.-Cuban relations went back into a tailspin. As always, he was in the driver's seat.