What is the rule about taxpayers being able to sue the government?

I know there was a case in the Supreme Court, decided Monday, that limits the right of taxpayers to sue the government alleging that spending is unconstitutional. I assume it had to do with the issue of 'standing' - who has the right to sue.

Does anyone have any further details. I should know this but am unable to look it up right now. thanks.

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Answers:
I don't have the case either but it has always been the law that being a taxpayer does not confer standing to challenge how one's taxes are spent.

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