Translation and Paraphrase: Negation Scope in 'not ... because ... but because'

Error: the negation is attached to the wrong element. Her version says the plan was not rejected; the original says it was rejected, but not for the stated reason.

Tests that settle it:

1. Cleft test. Rewrite as a cleft: 'It was not because it was expensive that the plan was rejected, but because nobody could explain who would pay for it.' In the cleft, 'not' sits immediately before the because-clause, so it can only negate the reason. That is the structure underlying the original.
2. Correlative test. 'not A but B' contrasts two items of the same type. Here A and B are both because-clauses, so 'not' must scope over the first reason. If 'not' negated 'rejected', the 'but because' clause would have nothing to contrast with and the sentence would collapse.
3. Logic test. Ask what the writer is arguing about: cost versus accountability. The point is that expense was not the objection.

Corrected translation: 「その計画が却下されたのは、費用がかかったからではなく、誰がその費用を払うのかを説明できる人が誰もいなかったからだ。」

Habit to fix: she read left to right and stopped at 'not'. Read to the end of the sentence first, locate the contrast frame ('not ... but ...'), and only then choose the Japanese predicate. Word-for-word correspondence is not a check on meaning.

Best paraphrase: 'It was impossible for anyone to explain who would pay for it.'

• 'It was ...' requires a complement after it, so the subject 'nobody' must be re-expressed. 'It was nobody could explain...' is ungrammatical: a finite clause cannot follow 'was' without 'that', and 'It was that nobody could explain...' shifts the emphasis onto the fact rather than the inability.
• Keeping 'anyone' inside a negative frame ('impossible for anyone') preserves the original's force: no person was able to give an answer.
• The shorter 'It was unclear who would pay for it' is grammatical and idiomatic, but it shifts the meaning slightly: 'unclear' describes the state of the question, whereas the original describes the failure of the people to answer it. In a passage about the committee's evasiveness that shift costs marks; in a neutral context it does not.
• Rule for paraphrase items: preserve (i) the proposition, (ii) who did what to whom, and (iii) the strength of the claim. Change the grammar, not the responsibility for the action. If the word limit forces a choice, keep the agent and simplify the verb, not the reverse.

Her sentence: 'It is not the problem whether we have a budget.'

• 「〜ではない」 with a nominalised clause (「予算があるかどうかが問題なのではない」) is a cleft: the negated element is the predicate - 'the problem' - not the budget question. English marks this with 'The problem is not whether ...', where the negative sits on the complement after 'is'.
• Her version keeps Japanese information order (topic first, negation last) and produces 'It is not the problem whether ...', which reads as though 'it' and 'the problem' were two different things, and leaves 'whether ...' stranded at the end.
• Fix (neutral): 'The problem is not whether we have a budget (but how we spend it).'
• Fix (formal): 'Whether we have a budget is not the issue.' Here the clause becomes the subject, which is the natural English way to front a topic.
• Transferable point: when a Japanese sentence ends in 「〜のではない」, the English negative belongs beside the element being denied - normally the complement after 'be' - not at the end of the clause. Check by asking 'what exactly is being denied?' and put 'not' there.