...how much of this is driven by the rancid and stale Cold War rhethoric of the right?

A lot of ways to respond, few of them quickly.

One, a lot of empirical studies over time which I respect indicate that there's a very consistent foreign policy establishment which sets up the overall guidelines, values, and boundaries to be followed, and most of the time the squabbling by politicians is on where, how, and to what extent to push policies within those limits.

This is an overwhelmingly upper class dominated society, and this major factor is almost completely ignored in our society (unsurprisingly), and it is almost universally assumed that the wealthiest and most powerful people in our society are far, far stupider and weaker than we are here on this blog and that they could never, ever be so clever as to successfully create institutions and groups and incentives / disincentives to ensure that policies, where ever possible (given reality), lean towards their interests. (Even FDR's most interventionist reforms, which right wing nuts screamed were "socialist", were often generated by policy groups directly sponsored by upper class wealthiest of the wealthy patrons, so as to stabilize the country they didn't want to fall apart.)

In my view it is overwhelmingly this policy environment which creates the sense among our elites of what is normal, sensible, permissible, and politicians then fight over the details. Significant fights, possibly world-ending fights -- who knows, we came very close to nuclear war over Soviet missiles in Cuba while the US put missiles in Turkey -- so when I say "details" I don't mean "minor." I can't under any realistic circumstances imagine JFK going to bat for Cuba's ability to be independent and socialist, even if not one soul in the nation had emitted one solitary word of "rancid and stale Cold War rhetoric" from the right against such an idea.

At some stage, though, the argument begins to recurse into itself. Did the "rancid and stale Cold War rhetoric of the right" cause everything? If so, that's an awful lot of independent power of rhetoric. Or was there a set up of power which meant that this rhetoric had an impact?

There may have been "rancid and stale Cold War rhetoric of the right" used to justify Ronnie's bloody crusades slaughtering civilians all across Central America and Southern Africa, and that may be how he perceived it, as a Cold War fight, but then, he likely would have done quite similar things had he believed the Martians were behind the Central American moves toward independence from US-backed dictatorships and plutocracies, or in Angolan and Mozambican independence from Portuguese colonialism and South African fascist imperialism, and Reagan and his worshippers could have used anti-Martian rhetoric. Whatever worked and whatever they managed to believe. As long as it worked, they would have used whatever rhetoric necessary to crush moves toward independence and struggles against plutocratic rule in the interests of US and Western-linked elites.

In any case, it's helpful to bear in mind that this was all a choice, and a rotten one. We all would have been better off had our foreign policy establishment not rampaged the world supporting thugs and murderers and fighting the legitimate democratic and just independence of many populations. If Central and South Americans had been genuinely encouraged by the US leadership to become more democratic, and not "vote our way or we'll kill you" style either, we could have had much more peace and development for 40 odd years now. More countries to trade with. Less pressures for immigrants to flee their disastrous countries and economies. Et cetera.

Your citations of Clinton's policies seem to support what I was suggesting, which is to focus mainly on the decency or indecency of policies themselves, not the party identification of their backers, unless that's a vital part of the actual political context.

Yes, Clinton's Cuba policies were marginally saner than the classically failed US policies demanded by the Cuban exile nutbag community and the World Anti-Communist League fascists, but our abilities to analyze policies in and of themselves need neither begin nor end with the political personalities behind them, except when we're focusing on biography or predicting future politicians' actions based on past behaviors. In this context, the US' Cuba policies are still insane, idiotic, and harmful to both nations' interests -- even the premiere capitalist spokesperson from the US Chamber of Commerce agrees, though for different reasons than I might cite.

On the plus side, one could argue that Bush Jr's self-entrapment in Iraq and his worship of idiotic pseudo-cowboy non-diplomacy actually encouraged the greatest degree of South American independence and self-development we've ever seen, so there probably is some degree to which many, many South Americans ought to be sadly grateful that the US' foreign policy establishment lost its ability to prioritize US elite hegemony over Latin America. I'd like to believe that was now a "fact on the ground," permanent, irreversible, and I see some signs that this may be the case, but I wouldn't rest too easy on that assumption.