I'm not sure that you can have the moral high ground in a hypothetical scenario where Cuba conspires with Iran to attack the US. At that point both parties are banking on "might makes right".
I was replying to OP who sketched the scenario
> Worst outcome is the US attacks Cuba ..
As you probably know POTUS was announcing already that Cuba would be next.
If Cuba is attacked they are by international law allowed to strike military targets inside the US.
The US isn't magically off limits.
Cuba's government is not the Cuban people, that's part of the whole point isn't it?
Well, in this hypothetical scenario you can just as well say that Cuba is defending from the future threat from USA, the same way USA is now defending from future threat from Iran.