I have another sentence I'm grappling with *[see footnote for context]:
I'm pretty sure from my dictionaries that 判断 means "judgement" but cannot figure out what makes sense for 裁量. All I can find is "admeassure[ment]", "discretion" or "judgement" again, which would be weird, because the compound would mean "judgement judgement". None of these options seem to make sense, so some interpretation help would be appreciated.
I understand the rest of the grammar. Whatever this word compound is "cannot become", which in English would mean "cannot be [in the future]". Thus it's crucial to understand this compound.
The translation reads "I won't be able to use this to figure out whether or not he's Kira." so the translators seemed to have just ignored one or both words from the compound.
Note on context:
The speaker is a detective who is playing tennis with a suspect in the "Kira" case in order to try to figure him out. Kira is a notorious serial killer.