(This is very similar to how to conjugate verb in dependent clause inside subjunctive mood — but that question has no accepted answer and this question is about independent, not dependent clauses.)
The sentence in question (referring to a virtual machine, a computer program that simulates an actual hardware device):
- It acted exactly as if it were a hardware machine and its power was/were[?] cut.
While the "as if" forces the first verb into the imperfect subjunctive "were", I think both "was" and "were" are syntactically acceptable for the second verb but have different semantics:
- It acted exactly as if it were a hardware machine and its power were cut.
expresses the idea of both clauses implicitly being introduced by "as if" — in other words, it acted exactly like a hardware machine, and acted exactly like its power was cut. Obviously there would be no argument (except with the wordiness) in making this explicit:
- It acted exactly as if it were a hardware machine and as if its power were cut.
—the second "as if" demands the subjunctive just as the first does.
- It acted exactly as if it were a hardware machine and its power was cut.
expresses the idea that only its being a hardware machine is counterfactual; having imagined such a machine, the possibility of the imagined machine's power being cut is not counterfactual.
Thus my intuition is that using "was" for the second verb more correctly expresses the sentiment. Going back to sentence #3 with two "as if" clauses: while grammatical, that sentence seems slightly nonsensical, since cutting power is something that is impossible to do to a virtual machine, which lacks a power supply. "[The virtual machine] acted as if its power were cut" standing alone would be a sentence without any sensible meaning. Only in imagining the counterfactual hardware machine can the power being cut have meaning, and that meaning is not a counterfactual, but an eventuality.
This is my intuition from the old minimal pair,
- If my boss calls, tell me immediately.
- If the President were to call, tell me immediately.
My boss calling is an eventuality; the President calling is unlikely to the point of being a near-counterfactual.
And similarly, power failing to a hardware device is an eventuality, so I'm inclined towards the indicative, not the subjunctive.
I haven't yet entertained the possibility of:
- It acted exactly as if it were a hardware machine and its power were to be cut.
because this seems needlessly wordy, even though it is technically a different conjugation — the "as if" isn't distributive here — and it sounds grammatical to my ears. If, for some reason, I needed to make explicit the conditional sequencing of the imagined machine and its power being cut, this sentence's wordiness might be acceptable.
To restate the question explicitly: is either "was" or "were" obligatory in the second clause, or are both acceptable? And, if they are both acceptable, do they express slightly different ideas, and if so, in what way? (To restate implicitly: am I right?)
p.s. One digression: Am I correct that the second clause is an independent clause? I asserted that from the outset, but I'm not so confident.
The "its" makes it possible it is a relative clause—it could be rewritten as "...machine whose power was cut", but "its" could be entirely dropped, resulting in an unequivocal independent clause "...machine and power was/were cut", so I think it's an independent clause even though it contains a referring pronominal.