Could a middle-of-the road solution prevail in Heien v. North Carolina, the fascinating and important Fourth Amendment case being argued on Monday? The parties and most commentators have understandably focused on the more absolutist positions in the case, but alternative dispositions are available. In particular, the Court could rule that mistakes of substantive law are reasonable for Fourth Amendment purposes only when the police have relied on clear guidance from authoritative sources, like courts or legislatures. That middle-ground approach would give the government a partial victory on the legal standard applicable in future cases, while affording the defendant a victory in the case at hand.
The question presented in Heien seems pretty stark: “Whether a police officer’s mistake of law can provide the individualized suspicion that the Fourth Amendment requires to justify a traffic stop.” This formulation seems to ask whether an officer’s mistake of law during a traffic stop can ever satisfy the Fourth Amendment. If the Court answered in the negative, that would certainly be good news for the petitioner, who was stopped based on suspicion that he had violated a traffic requirement that (state courts later concluded) did not actually exist. Much of the briefing focuses on this broad framing. For example, the petitioner argues that if ignorance of the law is no excuse for average people, then it shouldn’t be an excuse for police either. Orin Kerr and other commentators have taken up this salient line of reasoning. For my part, I’ve blogged about how the question presented is in tension with the rule of lenity and informed by arguments from history.
But the petitioner could actually prevail under many narrower holdings, and the petitioner’s briefing effectively acknowledges as much. Consider for example this passage from the petitioner’s reply brief:
Even if this Court were to deem good faith pertinent to the legality of traffic stops based on mistakes of substantive criminal law, an objectively reasonable misinterpretation of a never-before-construed statute still would not supply reasonable suspicion. Contrary to the State’s and Solicitor General’s arguments, tolerating this sort of mistake would establish pernicious incentives for police officers at the expense of individual liberty. It is one thing to tolerate police officers’ mistaken reliance on clear dictates issued by courts or legislatures; it is wholly another to tolerate officers’ own legal mistakes, even if supposedly reasonable.
In other words, we want and expect police to take seriously “clear dictates issued by courts or legislatures.” And when those “clear dictates” are wrong, that error is arguably attributable to the “courts or legislatures” that generated the relevant guidance—not to the police who quite reasonably followed it. As the passage above argues, this approach helpfully aligns incentives, in that it encourages police to think hard about the right answer whenever they lack clear guidance from legal experts. It also comports with widespread intuitions about what can “reasonably” be expected of police.
This relatively nuanced approach also has the advantage of comporting with the government’s reading of Michigan v. DeFillippo, where the Court seemed to say that police complied with the Fourth Amendment when they sought to enforce what turned out to be an unconstitutional ordinance. Instead of re-characterizing DeFillippo as a remedies decision (as the petitioner primarily argues), the Court could simply read its apparent Fourth Amendment holding narrowly. In Heien, there was no clear guidance from the legislature or from courts as to the relevant substantive law. Instead, there was just a confusingly written statute that (it seems) had never been authoritatively construed. Therefore, DeFillippo could easily be read not to apply in Heien.
In response, the United States as amicus pointed out that the state courts viewed the relevant statutory question as open to reasonable disagreement, given the relevant state statutory text and structure. And the United States also noted: “Cases involving similar stops had been adjudicated with no suggestion that a broken light was lawful.” These arguments fall short of showing that the police were relying on the legislature or courts. Instead, the police simply faced a challenging legal question that the legislature had created and that the courts hadn’t yet been asked to resolve. It does not even appear that the police sought out relatively expert legal guidance within the executive branch.
Notably, the government’s argument is in tension with its normal insistence that sub silentio holdings are not holdings at all. In another case being argued this sitting, for example, the United States cited Webster v. Fall: “Questions which merely lurk in the record, neither brought to the attention of the Court nor ruled upon, are not to be considered as having been so decided as to constitute precedents.” Right or wrong, the government’s idea that police are uniquely entitled to rely on sub silentio holdings is yet another form of Fourth Amendment exceptionalism at work in Heien.
Will even a single Justice be interested in exploring this kind of middle-ground result? Perhaps not. But it’s still an important aspect of the case before the Court.
Re’s Judicata 
Whether or not a seizure is reasonable must be determined by the state of the law on the date that the stop is effectuated.
I agree, if the law on that date is clear (according to the courts or the legislature) the stop is reasonable even if a court subsequently declares that the law relied upon by the cop to justify the stop was inapplicable. But if the law on the date of the stop is unclear (as is the case in Heien), a stop based on that law is reasonable if, under the totality of the circumstances, a reasonable cop would have interpreted that law as justifying the stop. And the fact that a court subsequently determines that the law did not justify the stop is irrelevant to the reasonableness (or lack thereof) of the cop’s conduct.
Your middle-ground solution doesn’t comport with the facts in Heien, because the law on the date of the stop was unclear. And I don’t see the five justices in the Navarette majority holding that the stop (in Heien) was unreasonable because the law was unclear on the date the stop was made, and a court subesquently determined that the law relied on by the cop did not permit the stop.
I see the Court applying a permutation of its federal habeas corpus jurispridence framework whereby a federal court is prohibitted from granting a habeas petition unless the state court’s application of federal constitutional law was unreasonable according to clear Supreme Court holdings that were in existence on the date the state court rendered its merits decision.
In any event, as usual, your insightful, unique analysis is very much appreciated and respected.