A ruling by a federal court Monday drew the ire of the ACLU after siding with the U.S. government and rejecting a challenge brought by four U.S. citizens over their inclusion on the No Fly List, thus leaving the men, according to the civil liberties group, "in an indefinite Kafkaesque nightmare."

Inclusion on the secret database—which represents part of the government's terrorism watchlisting system—means a person is blacklisted as a suspected terrorist and banned from flying into, within, and from the United States.

While the government in 2015 put in place a court-order revised redress system, the ACLU says that system falls short because it deprives people of a fair process to dispute their placement. The group therefore continued its legal challenge.

The lower court that found the new system satisfied constitutional requirements, said Hina Shamsi, director of the ACLU's National Security Project, erred. "The court largely rested its incorrect conclusion on a novel ground—that 'undue risk to national security' justified the government's secrecy and deficient process. But no other court has ever permitted blanket assertions of national security risk, untethered to specific justifications that courts then adjudicate, to legitimize a process so flawed," Shamsi wrote earlier this month.

The Portland, Oregon-based federal appeals court, however, saw things differently. Circuit Judge Raymond Fisher wrote

The panel held that the district court properly rejected plaintiffs' as-applied vagueness challenges. The panel determined that the No Fly List criteria are not impermissibly vague merely because they require a prediction of future criminal conduct, or because they do not delineate what factors are relevant to that determination. The panel held that the criteria are "reasonably clear," in their application to the specific conduct alleged in this case, which includes, for one or more plaintiffs, associating with and financing terrorists, training with militant groups overseas, and advocating terrorist violence. Furthermore, the criteria are not so standardless that they invite arbitrary enforcement, at least as applied to plaintiffs. Because the panel concluded the No Fly List criteria were not vague as applied, it declined to reach plaintiffs' facial vagueness challenges... [The panel] concluded that the procedures provided to plaintiffs were constitutionally sufficient, or that any error was nonprejudicial. The panel determined that given the national security concerns at issue, and with the exceptions noted, the government had taken reasonable measures to ensure basic fairness to the plaintiffs and followed procedures reasonably designed to protect against erroneous deprivation of plaintiffs' liberty.

The ruling, Shamsi said Monday, "lets the government hide behind overblown secrecy claims to deny our clients' constitutional right to due process."

"Our clients have been unable to fly to visit family, pursue job opportunities, or fulfill religious obligations for over nine years based on vague criteria, secret evidence, and unreliable government predictions. These citizens have never been charged with a crime and asked for fair notice and a fair process to clear their names and regain rights most Americans take for granted."

"Instead," she continued, "the court has left them trapped in an indefinite Kafkaesque nightmare."