Se habría visto precisado a dejarse llevar

[Quaeso]

Pero si [el hombre quien estuvo en el desván] hubiese querido llevárselo, no hubiera tenido que esperar tanto tiempo, pensaba Marcelino. ¡Tantas veces había estado él casi solo en el convento, por la huerta y por el campo! Con un hombre no habría podido luchar y se habría visto precisado a dejarse llevar quieras que no. -Marcelino ch.3

The phrase se habría visto precisado a dejarse llevar has a lot of verbs in it. I think that I get the main idea, but what are the subjects of dejarse and llevar?

[aleCcowaN]

It's the same subject all along the expression: the young and, to some degree, defenceless Marcelino. In that hypothetical situation, Marcelino feels pressed and obliged to do something in a context of lack of freedom or choice (verse precisado), consisting in allowing himself to be abducted without resisting (dejarse llevar).

[Quaeso]

Thank you, I see how the subject of dejarse would be Marcelino, but if Marcelino were also the subject of llevar, then it seems that he would be the one abducting (that is abducting either himself or some other object), which seems unlikely here.

[aleCcowaN]

Dejarse llevar isn't a periphrastic construction but it's especial in some way as the transitive verb llevar becomes passive just for being an infinitive used as a complement of the verb dejar in its reflexive form. Another good example of this is hacerse respetar.

Hundreds of examples come from this couple of verbs: dejarse engañar, hacerse valer, dejarse convencer, hacerse odiar. This last example is very clear: in se hizo odiar is patently obvious that other people are the ones hating the subject; they are in turn the subjects in those acts of hating. However, in hacerse odiar it's clear that the original subject has done everything possible in order to trigger and fairly deserve that hate, a hate that is just the natural and almost inevitable consequence of the actions of the original subject (this use even exclude the intervention of supernatural agents either tempting or hardening hearts)

In summary, in dejarse llevar, llevar is a passive infinitive that takes the subject of the main verb dejar (in its reflexive form), in this case, Marcelino.

There are many instances in Spanish where a transitive verb acquires a passive meaning just for being a complement, for instance, difícil de entender or imposible de resolver, which involve adjectives, or no ser algo de extrañar, which involves a complex verbal structure.

Should you learn these cases one by one? I don't think so. Native speakers understand that a chain of infinitives following a conjugated verb keeps the subject of the conjugated verb (quiero conocer a tu prima e invitarla a tomar un café y con suerte, si todo sale bien, invitarla a bailar -subject I, not your cousin). The same with compossite or chained infinitives: the chain takes the subject of the first verb in the chain (dejarse llevar, ponerse a pensar).

But this is now too long! Me dejé llevar (I got carried away)

[Quaeso]

Thank you, understood.