Imagine you're a lawyer entering the courtroom to select the 12 men and women who will decide the civil case you've been preparing for nearly a year. Sitting in the gallery's second row, squeezed in among dozens of other ordinary Maryland citizens grudgingly or enthusiastically performing their civic duty, is the chief justice of the United States, John G. Roberts Jr.

Would you want him on the jury?

That was the question confronting a pair of attorneys last week at the Montgomery County Circuit Court in Rockville, Maryland. Roberts was Juror No. 49 in the pool under consideration for a case that stemmed from a car wreck, according to the Washington Post. After answering two questions in open court and then speaking quietly with the judge and lawyers, he was not selected for the jury.

By title alone, Roberts would be the most qualified juror in the country. He's the crew chief of the nation's courtroom umpires, overseeing not only the eight other justices of the Supreme Court but the entire federal judiciary. At his own, nationally-televised voir dire in 2005, he famously won over Democrats and Republicans alike by humbly vowing merely to "call balls and strikes."

Yet the choice for a litigator considering citizen John Roberts is not as simple as it sounds. "Assuming the chief justice would be exceptionally committed to hearing any case fairly, he would potentially be an ideal juror," said Suzanne Goldberg, a former litigator who now teaches civil procedure at Columbia Law School. "The risk, of course, is that most lay people would likely defer to him on legal judgments even if the judge instructed them not to do so." Goldberg said that if Roberts were selected for a trial, the judge in the case might choose to "reinforce the guidance that each juror's vote has equal weight." He might be the chief justice, in other words, but feel free to disagree with him.

Kathy Arberg, a spokeswoman for the Supreme Court, said that while several other justices had reported for jury duty in recent years, the Court did not keep records on whether any of them had served on a trial. Roberts made no apparent attempt to be excused from the trial, the Post reported. The judge asked the potential jurors to speak up if they had relatives in the medical profession, and Roberts said that his sister was a nurse in Indiana. When Judge Ronald Rubin then asked, per the custom, whether that would prevent him from being "fair and impartial," the chief justice replied, "Nope." The high court does not keep a particularly busy schedule, and Roberts was not due back on the bench until Monday. The lawsuit in Maryland was scheduled to be a two-day trial, and the jurors ultimately selected found in favor of the plaintiff on Thursday.

While it's rare, if not unprecedented, for a Supreme Court justice to sit on a jury, it not unheard of for other high-ranking judges. "Judges do get summoned and do serve," said Paula Hannaford-Agor, director of the Center for Jury Studies. She pointed to the example of Shirley Abrahamson, the chief justice of the Wisconsin Supreme Court who has served on two juries during her tenure. Traditionally, the bigger bugaboo for trial lawyers has been the prospect of having other lawyers sit on their juries, so much so that for decades, some states formally exempted them from serving. Much of the concern was simply about subjecting themselves to a high-stakes form of peer review, but trial lawyers also worry about the "outsized influence" of having someone on a jury who is a professional expert in the art of argument and persuasion. Goldberg said that when she reported for jury duty shortly after New York removed its lawyer exemption in the 1990s, one of the trial attorneys pulled her aside and told her that both sides in the case had agreed not to put any lawyers on the jury. "I think that has diminished somewhat, but it’s fairly common still," she said.

Lawyers can use their peremptory challenges to strike potential jurors for pretty much any reason as long as it's not discriminatory (such as challenges based on race, gender, or in some states, sexual orientation). That could include celebrity, or even Roberts' very public record on the bench. "Jury selection is fundamentally about enabling both sides to have an open-minded and neutral jury hear the case, but each side will at the same time be seeking jurors who it thinks will be more favorable to its client," Goldberg said. Yet it probably would be unwise for any lawyer to suggest in open court that the chief justice of the United States was too biased to sit on a jury, especially in a case that had nothing to do with interpreting the Constitution. "That is very dicey ground," Goldberg said.

John Roberts' encounter with the jury system, though, ended in entirely typical fashion. Like three out of every four jurors who report for duty, he was sent home. According to the Post, the lawyers in the Maryland case on Wednesday found their 12 jurors long before they got to famous No. 49.