A legal dispute concerning the length of a state inmate's beard could result in a broader decision by the U.S. Supreme Court about when prison authorities can limit religious exercise for the sake of security. Justices heard oral arguments for the case, Holt v. Hobbs, on Oct. 7, which pits Gregory Holt, an state prison inmate in Arkansas, against Ray Hobbs, director of the Arkansas Department of Corrections.

Several questions by the justices suggested they were interested in finding a general legal principle that could be applied beyond the specific circumstances of a prison's grooming policy.

"One of the issues with a case like this is where to draw the line," said Chief Justice John Roberts, referring to the extent to which courts should defer to the expertise of prison officials in balancing religious liberties with security concerns. "What's the legal principle? If there is no direct legal principle, then isn't it a situation in which you would employ deference to the administrative judgment?"

Without a broader principle, justices raised the concern that courts could get bogged down in the technical details of each prison's grooming policy. "I don't want to take these cases half inch by half inch," said Justice Antonin Scalia.

The petitioner in the case, Gregory Holt, is an inmate of the Arkansas Department of Corrections. He wanted to grow a beard because he follows the Salafi school of Sunni Islam, which teaches Muslims to follow the Prophet Muhammad's example by growing a beard. The prison has a policy that prohibits inmates from growing beards beyond one quarter of an inch. (The policy includes a medical exemption, which allows beards to reach a half inch in length.)

Through the prison grievance process, Holt asked to be allowed to grow his beard to a half inch, which he saw as a compromise between the prison's beard policy and his religious beliefs. After state authorities declined his request, Holt sued in federal court, claiming that the prison's beard policy violates the Religious Land Use and Institutionalized Persons Act (RLUIPA).

The 2000 law prohibits prisons and local governments from imposing a substantial burden on the religious exercise of people living in an institution, including a prison. However, the statute also says that government can still impose a burden if it can show it is the least restrictive means of furthering a compelling governmental interest. The legal standard applied in RLUIPA is called strict scrutiny and tends to favor individual rights over government interests.

"Judicial deference is ordinarily a concept at odds with strict scrutiny," wrote Steven Schwinn, a professor at The John Marshall Law School, in a preview for the case. "And the strict scrutiny standard is a strange standard to apply (in its most rigorous form) because courts historically have been extremely deferential to prison authorities."

The case could be significant, Schwinn wrote, because it gives the court a chance to weigh in on conflicting priorities within RLUIPA of applying strict scrutiny and deferring to the expertise of prison officials when there is a compelling governmental interest, such as maintaining safety within a prison.

Douglas Laycock, the attorney representing Holt, said the case was a chance to clarify at what point courts should not defer to the judgment of prison officials. "What [Arkansas prison officials] really seek is absolute deference to anything they say just because they say it," he said. "There may be deference to prison officials, but there must be concrete limits to that deference."

Justice Sonia Sotomayor asked Laycock to outline a legal principle that could be applied in general to determine when deference would be appropriate. Laycock said courts should consider what other jurisdictions do, what the evidence shows and whether a prison's policy is consistent. He said that state prisons in 43 other states allow inmates to grow beards of unlimited length without a single documented example of an inmate using a beard to smuggle contraband. He also noted that Arkansas itself allows half-inch beards for medical reasons. Therefore, the courts should question whether the quarter-inch beard policy is merited, despite what prison officials say.

Courts could still factor in prison officials' reasoning for burdening religious exercise, Laycock said, but only with sufficient evidence. "They have to show material effect on security," he said. "I think what we have in this case is exaggerated fears."

Scalia challenged the notion that if most state prisons allow beards, then Arkansas didn't have a compelling interest in keeping quarter-inch beards. "[Arkansas] can just say, 'the other states are wrong. We think this is dangerous,'" Scalia said.

In a legal brief supporting Arkansas, 18 state attorneys general argued that comparing grooming policies across states is a mistake anyway. They explained that prisons generally make tradeoffs between the type of inmate confinement and the grooming policy. Arkansas uses open-barrack housing, which allows inmates more opportunities for socialization, entertainment and education, according to the brief. At the same time, open-barrack housing gives more opportunities for exchanging contraband and using weapons on one another, which is why prisons with open-barrack housing tend to have stricter grooming policies. Conversely, prisons that place inmates in one- or two-person cells allow greater freedom with beard length, the brief said.

Arkansas Deputy Attorney General David Curran took issue with another part of Laycock's test for deference: proof of a security risk. While he conceded that he couldn't offer an example of an inmate in a prison outside of Arkansas using a beard to smuggle contraband, such examples could exist but be buried in incident reports. "It's the nature of prisons," he said. "That's just a problem of empiricism in the prison environment."

In their brief, the state attorneys general supporting Arkansas also challenged the notion that deference only be granted given sufficient evidence. "Prisons should not need to cite specific instances of their policies failing to prove a compelling interest," they wrote. "Prisons should be able to adopt prophylactic rules to proactively limit risk."