One of the few limitations on the judiciary has traditionally the concept of standing. Basically, federal courts can only resolve 'cases and controversies.' This, in turn, means that there must be a real plaintiff and a real defendant. To be a plaintiff, you must have suffered a concrete injury, and that injury must affect you in some generally particularized way. Thus, many, many courts have thrown out cases based on merely being a federal taxpayer.

Before last year, this case would get tossed out quickly on this ground - the plaintiffs really aren't hurt more than anyone else. Their one glimmer of hope is the global warming case you mentioned. It's probably easily distinguishable, though, because there the State of Mass itself alleged its tax revenues would go down because the EPA failed to enact regulations, which would have stopped global warming(!), which would have prevented sea levels from rising, which would have caused a net loss of coastline, which would have given some taxpayer an excuse not to pay their taxes. I kid you not.