Congress has gone out of its way to provide inmates certain constitutional rights under the First Amendment's clause guaranteeing the free exercise of religion. How this came about is a long story which starts with a Supreme Court decision written by Justice Scalia in 1990, Employment Division v. Smith, 494 U.S. 872 (1990), which altered the legal standards for Free Exercise claims. Congress tried without success to overrule the Smith ruling, and when the dust settled, the best way to do it was the Religious Land Use and Institutionalized Persons Act, or RLUIPA.
Under RLUIPA, the states cannot restrict inmate religious practices without a compelling reason. Even if the reason is compelling, the government has to show that the restriction was the least restrictive way to achieve that compelling interest. (Because of what the Supreme Court did in Employment Division v. Smith, RLUIPA's consequence is that inmates have greater religious freedom rights than the rest of us). This all plays out in Jova v. Elmore, decided on September 28, where the Second Circuit reinstated the case on behalf of two inmates who practice the Tulukeesh religion. The inmates represented themselves on appeal, by the way.
Borrowing from the legal reasoning of other federal appeals courts which have taken up this issue, the Second Circuit find that prison security is a compelling government interest. But the government has to support its argument with evidence, not speculation or after-the-fact rationales. In this case, the plaintiffs claimed their religion requires a group setting and they cannot worship alone. The jail responded that in order to have a group setting, the inmates have to find outside religious clergy to officiate. Among other things, the inmates also want martial arts training as part of their religious exercises and a particular diet. The government is able to convince the court with voluminous evidence in the form of affidavits that the restrictions are "justified by powerful security and administrative interests."
Not so easy on the second set of legal issues on appeal: whether the government used the least restrictive means to protect security in the prison. As it does not want religious meetings to serve as a proxy for gang activity, the government is able to justify its requirement that the inmates use an outside chaplain to officiate their religious exercises. If the inmates cannot find someone, an inmate can facilitate the meetings provided "the religion is known outside the institution." For obvious reasons, the government is also able to prevent martial arts training ("potentially violent physical activities") in the jail.
However, it is unclear to the Court of Appeals whether the dietary restrictions are narrowly-tailored. The inmates need a vegan diet that does not include soybeans or certain soy-related products. The Court of Appeals wonders why the jail cannot provide an entirely vegetarian menu to inmates who request it. If the jail can do so, then its proposed alternative menu may not be acceptable. The case is remanded to the district court to figure this out.