Two foundational principles of the American legal system will face off at the United States Supreme Court Tuesday: the expectation that jury deliberations will be confidential, and remain so after a verdict has been reached, versus the belief that explicit racial bias taints legal proceedings to an unconstitutional degree.

With the nation embroiled in a tense debate over racial bias throughout the criminal justice system, the case could establish an important national precedent regarding when jury verdicts can and can’t be investigated. Moreover, the case gives the court an opportunity to make a statement on racial bias in the courthouse.

On the surface, the case is fairly straightforward. In 2007, when a Hispanic racetrack worker was on trial for sexual harassment, one juror told other jurors that he thought the defendant was guilty “because he’s Mexican and Mexican men take whatever they want.” In his experience as a former law enforcement officer, the juror said, “9 times out of 10 Mexican men were guilty of being aggressive toward women and young girls.”

The worker, Miguel Angel Peña-Rodriguez, was convicted, and two of the jurors told defense attorneys about the comments. Arguing that his right to a fair and impartial jury had been violated, Mr. Peña-Rodriguez sought a new trial.

A series of lower courts narrowly ruled against him, stating that Colorado’s “no-impeachment rule” – preventing jurors from testifying after a verdict about what happened during deliberations – does not include an exception for incidents of racial bias. The high court now must consider whether an offense can be so great that it outweighs those vital protections to the jury process.

“The court has recognized that there are opportunities for racial and ethnic bias to operate in the criminal justice system, and they say, ‘We’re going to take all steps we can to eliminate, to the extent we can, racial bias and discrimination in the criminal justice system,’ ” says John Blume, a professor at Cornell Law School. “Cases like this test whether the court means what it says.”

Clues from the court

Most states have no-impeachment rules, but they don’t all make an exception for racial bias. Lower courts have split over whether the Sixth Amendment right to a fair and impartial jury trumps state interests in keeping jury deliberations private and preserving the finality of jury verdicts.

Two years ago, the court indicated that it might be willing to create such an exception.

In a case involving a juror who had both withheld information during jury selection and expressed bias during deliberations, the justices held unanimously that jurors couldn’t testify about jury deliberations, even to reveal dishonesty during jury selection.

But a footnote in that decision added that “there may be cases of juror bias so extreme that, almost by definition, the jury trial right has been abridged. If and when such a case arises, the Court can consider whether the usual safeguards are not sufficient to protect the integrity of the process.”

Racial bias – particularly the racial bias in the Peña-Rodriguez case – may be that extreme case, says John Paul Schnapper-Casteras, special counsel for appellate and Supreme Court advocacy at the NAACP Legal Defense Fund, which has filed a brief in support of Peña-Rodriguez.

For decades, he says, the court has consistently ruled that “racial prejudice is different and special, and that there’s a unique prerogative under the Constitution to eradicate that prejudice in the criminal justice system.”

“This is really extreme, it’s documented, it’s very explicit, and there’s already lots of case law showing that this kind of unambiguous discrimination is exceptional and should be rooted out,” he adds.

A slippery slope?

Some experts have concerns about the implications of creating such an exception, however.

Various briefs in support of Colorado warn of a slippery slope in which creating a general exception for racial bias precipitates defense attorneys harassing jurors for details of deliberations. Moreover, the exception could “open up even further with allegations of different types of alleged bias,” one brief argues.

“I think this is going to require an extremely difficult line drawing,” says Scott Greenfield, a criminal defense lawyer in New York and managing editor of the Fault Lines legal blog.

“What if one juror complains that another juror used the word ‘fortune cookies’ and must be racially biased against Asians?” he adds. “Different people have extremely different sensibilities about what constitutes racial bias.”

A brief in support of Peña-Rodriguez from four former Massachusetts judges argues that juror harassment can be mitigated by crafting ethical rules – as states like Massachusetts and Minnesota have done – prohibiting lawyers from contacting jurors in the course of investigating racial bias allegations.

“I would not stake my life on the expectation that lawyers are going to behave thoughtfully and respectfully,” says Mr. Greenfield. “There’s a huge risk that there will be lawyers going way over the top to dig up some dirt on a juror.”

Steven Schwinn, a professor at the John Marshall School of Law, admits that he has a “a mild worry” about that scenario manifesting itself, and that some of the justices might have similar worries. But he adds that he is “much more worried about racial statements in the jury system that go unaddressed.”

He anticipates that the justices will walk the same narrow path.

“I think they could tailor the opinion so it doesn’t open those floodgates any more than they’re already open now,” he adds. “The court’s been sending some signals recently, as recently as oral arguments [last] week in the Buck case, that it’s not going to tolerate racial bias in the criminal justice system – at least it’s not going to tolerate overt racial bias in the criminal justice system.”