In Peña-Rodriguez v. Colorado, decided by the Supreme Court this week, there was well-documented proof that racial prejudice played a role in the defendant’s conviction of sexual offenses. If we put the issue that broadly, who could disagree with the decision in Peña-Rodriguez’s favor? But we can’t just put the issue that broadly, because a lot turns on how that proof emerged and whose racism was proven.

The facts were pretty straightforward. Two jurors told the defense lawyer, who then told the judge, that one juror had made pretty clear during deliberations that he believed Mexican men were prone to machismo violence, and the fact he was Mexican pretty much argued for conviction. But as for the legal frame, now let us go from the broad to the very narrow. American law views, or even reveres, the jury room as a special, mysterious, or almost sacred space, where deliberations can take any form that the interaction of the jurors leads to. The inputs into the jury decision—most obviously the evidence, the lawyers’ arguments, and the judge’s instructions—are subject to full scrutiny on appeal. But our general doctrine is that what happens in the jury room stays in the jury room. Hence the losing party cannot “impeach” the verdict on the basis of information supplied by jurors on what was said or done in that room, even if that information could cast doubt on the fairness of the verdict. Although the exact form of this rule has varied, the dominant version is that a verdict can only be impeached if there was an “extraneous influence”, something from outside the room that wrongly entered it, such as a bribe or a threat or some other form of impermissible influence. The rule serves several purposes: The defendant, or any litigant, has ample opportunity to identify juror bias during the voir dire. And were we to allow extensive impeachment of the verdict, jurors might be unduly inhibited in their deliberations (the obligatory legal cliche here is the “chilling effect”) or might face hassling by lawyers, and the finality of verdicts would be threatened by messy disputes about who said what in the jury room.

Nevertheless, a fair number of states have added an exception where a juror overtly manifests racist attitudes in the jury room. The need to combat racial prejudice is simply deemed great enough to warrant this extra exception.

Fine—states can legislate any such rule they want on this subject, and had Colorado done so Pena-Rodriguez could have won under state law. But Colorado hadn’t done so. Thus, following the standard rule, the trial judge rejected Pena-Rodriguez’s claim, and the Colorado higher courts affirmed.

But the issue in Peña-Rodriguez was whether states are required to add this exception, that is, whether the federal Constitution so demands. The Supreme Court has now said yes, by an all-too-familiar 5-vote majority (only 3 in dissent because of the vacancy), with Justice Kennedy writing for the Court.

The Court’s decision will make moral sense to many, but it also illustrates how race can challenge the usual boundaries of constitutional law. When we think of race under the Constitution, we think of the Equal Protection clause as the obvious vehicle for rooting out prejudice and discrimination. But the Equal Protection clause is often an ill fit in the legal context, because establishing an Equal Protection violation requires proof of intentional governmental discrimination. So sometimes the Court at least considers finding some other doctrine to address racial prejudice, with uneven results. In the famous McCleskey case of 1987, when the Court saw proof that death sentences are disproportionately imposed on the basis of race (especially the race of the victim), it rejected the equal protection claim because the prejudice may have been unconscious and widely distributed among prosecutor, judge, and jury. So then it considered the Eighth Amendment cruel and unusual punishments claim, but still the arguably subtle and amorphous causes of the disparities were viewed as not quite enough for the Eighth Amendment to offer help. On the other hand, in the vexing area of so-called racial profiling (that’s a moral, sociological, or political term, not a legal term), where police may be motivated by unconscious racism or “implicit bias” in deciding whom to stop or search, some courts have found space in another doctrine that does not mention race or discrimination—the Fourth Amendment to supply a remedy.

By ironic contrast, in other situations, it is easier to establish an equal protection violation, but the legal context requites a lot of twisting of it to fit the case. So consider grand juries. The general rule is that if there is an illegality, such as prosecutorial misconduct, leading to a grand jury indictment, but the indicted person is then convicted in a fair trial, any claim arising from the grand jury is moot. After all, the clean verdict of guilt beyond a reasonable doubt renders irrelevant the grand jury’s tainted finding of probable cause. Except that if the grand jury illegality is racial discrimination in selection of the grand jurors, then the claim survives a fair guilty verdict at trial, because, well, we need strong measures to root out prejudice. The most famous twist is the Batson doctrine, arising in 1986. The prosecutor used a peremptory challenge to knock out a potential juror because of the potential juror’s race. And the prosecutor is an intentional state actor. But isn’t the juror the one who suffered the intentional discrimination, not the defendant? Well the answer may seem to depend on whether the defendant is of the same race as the juror, but as the very complex developments in post-Batson cases have made clear, that does not matter. Any defendant is granted standing to make the claim for the juror, through the legal magic of so-called “jus tertii” standing. Somehow when racial prejudice taints a criminal conviction, the Court will seek, and often find a way.

So back to Peña-Rodriguez. Was there intentional state-authorized racial discrimination? Should we say the racist juror was a state actor? Or that after the facts were revealed the state, through the court system, intentionally tolerated the juror’s racism? Those questions are tricky, or even metaphysical. But no matter, because Justice Kennedy did not rely on the Equal Protection clause—he turned to the Sixth Amendment right to a trial by an impartial jury. Racial prejudice is surely partiality, but there are lots of other types of partiality, which do not receive this level of constitutional scrutiny.

He had some indirect precedent for this move: Surely the Sixth Amendment guarantees a jury free of bias, but if the trial judge wants to keep the jury voir dire short and sweet and not allow very extensive questioning of potential jurors about possible bias, the Constitution will normally not step in. But in a certain set of cases, where the very nature of the criminal charge shows that the case is deeply imbued with racial issues, then the Sixth Amendment will entitle the defendant to reasonably extensive inquiry into racial attitudes.

And so in the new case, the Sixth Amendment was found supple enough to offer Peña-Rodriguez relief, and will do so for defendants suffering similar harm, at least where the juror prejudice is so egregious and material. But that leaves another question. Justice Kennedy could be accused of sneaking in an Equal Protection holding under the mask of the Sixth Amendment. If so, why limit the holding to race? Other classifications—religion, gender—have purchase under the Equal Protection clause. Or what about a juror who convicts on the basis of the defendant’s constitutionally protected political views—would the Sixth Amendment somehow draw on the First Amendment? The Court avoided addressing any such possible extension in this case. But if the Court ultimately wants to draw the line at race, it will be saying that because racial prejudice is the defining tragedy of American history it demands special recognition, and if that special recognition requires some, shall we say, flexibility in constitutional reasoning, so be it.

Robert Weisberg is the Edwin E. Huddleson, Jr. Professor of Law at Stanford Law School and Faculty Co-Director of the Stanford Criminal Justice Center