I’ve been reading Philip Ziegler’s biography of King Edward VIII. After describing the tour that the Prince of Wales made to the USA just after WWI, Ziegler relates various diplomats’ reactions to the tour. The French Ambassador to the USA, M. Jusserand, is quoted as saying:
Son succès a été complet auprès des gens les plus divers. Les Anglais n’ont jamais rien fait qui ait pu si utilement servir à effacer les anciennes animosités.
My question: why is the verb in the subjunctive mood in the relative clause?
Les anglais n’ont jamais rien fait qui ait pu si utilement servir à effacer les anciennes animosités.
‘The English had never done anything that might have been able to so usefully serve to efface former animosities.’
The subjunctive is used to suppose things regardless of whether they actually happen. In this example, the author is saying that this deal not only helped more than anything else the English did, it even helped more than things they might have done but didn’t. The subjunctive is a shorthand way to cover all this meaning in one word.
However, though the sentence is obviously correct, I couldn’t tell why (I’m nothing close to a grammarian). I asked my mother (who’s more competent than me on such a topic) who couldn’t tell either, but is going to try and dig up an explanation.
However, I’m wondering what tense the OP would expect instead. The alternatives could have been “n’ont jamais rien fait qui aurait pu” (conditionnel passé) or “n’ont jamais rien fait qui eût pu” (subjonctif plus-que-parfait). But if the OP was expecting, say, the indicative, it might be easier to explain why it couldn’t be used. Maybe.
Why couldn’t the use of the subjunctive in this case simply reflect the Ambassador’s desire to highlight his position as a judge, an interpreter of an historical vicissitude beyond his certain grasp? I essentially agree with Johanna, except that I, like clairobscur, don’t see any reason to assume anything about relative strength of historical possibilities. That’s going a bit too far, in my opinion.
I don’t have Grévisse handy, but I’m almost certain the explanation is likely to be fairly simple and straightforward – after all, there’s little doubt about the sense of the sentence, just about the reason for choosing the subjunctive rather than, say, the conditional. I’ll try to look it up and we can compare answers later after a bit more research.
If I be not mistaken, it were correct to say that French grammar calls for the subjunctive in far more, and more common, usages than does English. Would that the English usage were clearer!