Principles and Limiting Principles for SB8
Worrying about reasons, not slippery slopes.
Talking about the procedural niceties in the SB8 litigation (as here, or here, or here) may seem rather callous. The device SB8 invented could be used to target any rights one cares about, including First Amendment rights of speech or religion. It could impose enormous penalties, chilling conduct that's almost-certainly protected by the Constitution, whenever a small risk of liability would be too much to bear. And it could forestall in practice the very challenges that would declare these impositions unconstitutional.
Along these lines, Ilya Somin argues that the Court should set aside some potential worries about limiting principles, because the slope is far more slippery on the other side. The danger of aggressive SB8-style laws is worse than the danger that federal judges will get trigger-happy with their injunctions: "If this results in overbroad injunctions that cover some officials who don't have relevant authority, there is no real harm in that, as the effect will be simply to enjoin them from doing things they cannot do anyway."
I don't much care for the structure of SB8, and I'd much rather that such devices were never used. If one agrees with Ilya that the Court should overrule Hans v. Louisiana, and that it should declare private individuals free to sue states, seeking a determination whether a given private cause of action is unconstitutional, then that seems like an appropriate course to follow here.
But that's a different question than the one actually facing the Court. To date, the Court maintains that Hans v. Louisiana was correctly decided (and I agree with them!), that there's no constitutional right to preenforcement review, that federal courts are required to act only in cases filed on proper grounds and between proper parties, and so on. The demand for a limiting principles is part of a demand for principles—a demand that the Court be principled in reaching its decision, that its judgment follow from premises that it's willing to defend in other cases too.
In the United States v. Texas suit, for example, one might claim that the U.S. has authority to sue states whenever they enact an unconstitutional law. But if the U.S. doesn't have that broad authority (something the Solicitor General concedes), then we need a limiting principle explaining when it can sue states: not out of a fear that it might do so too often, but as part of a coherent and honest explanation of why this case differs from others. Even an explanation like "this case poses too much danger to individual rights" asserts a general principle, namely that the U.S. gets to sue states whenever not being able to do so poses too much danger to individual rights. And then one might need to defend that principle in the context of other principles—such as that of Grupo Mexicano, that the federal courts' powers to hear such suits are constrained by traditional doctrines of equity, or that of Article I, that "[a]ll legislative Powers herein granted shall be vested in a Congress of the United States."
The problem facing the Court isn't one of slippery slopes, trying to predict what consequences might flow from either decision and how best to avoid them. It's one of legal justification, trying to explain why either decision would consist with the rules as they currently stand. Courts are expected to be open and forthright about their justifications, rather than to call them as they see them. And if the Court isn't willing explicitly to limit its prior language in Ex parte Young, Hansberry v. Lee, Taylor v. Sturgell, etc., then it shouldn't adopt a rule in this case that abrogates that language sub silentio.
Fortunately enough, we already have people in our government who can make decisions without needing to be principled, without explaining the reasons for them, and without the constraints imposed by current law. These people are hired to take the law as it exists and to change it into something better: we call them legislators. The rights protected by the Constitution already apply in state courts, whenever a case arises involving them; if we need a new means of asserting those rights in advance, not already contained in current law, we might need Congress to provide it.
That "Congress won't act" isn't a good legal argument for judges' raising or lowering tax rates or declaring war or peace. It also isn't a good legal argument for judges doing other things for which they lack authority, tempting as it may often be.