Student or Learner
"...American sympathy rapidly evaropated, however, when Premier Castro, acting and sounding like a Communist dictator, failed to hold the free election he had promised, ..."
I wonder if simple past (promised) can also be used because it's evident that Castro's promise happened first and then his failing to hold it.
I like the past perfect also.
1) I am aware of the 'rule' that when there are two past actions, the earlier past action should be expressed by the past perfect tense.
2) But as you say, the meaning without "had" is just as clear. So from that point of view, "had" can be said to be unnecessary. So then the rule is requiring us to use an unnecessary word.
3) People may like the past perfect or feel it is better for various reasons, and of course it would be nice to know what those reasons are. Maybe they just feel that the rule requires the past perfect. Maybe they are used to using the past perfect, so it sounds better and/or (more) correct.
4) Are there sentences similar to yours in which clarity of meaning requires the use of past perfect? I can't come up with an example now, but that doesn't mean that such sentence cannot exist. Maybe someone can give us an example of such a sentence, and I won't be surprised if someone does.
Hopefully, there will be further comments.