INDIANAPOLIS – An American-born Taliban fighter imprisoned in Indiana will try to persuade a federal judge that his religious freedom trumps security concerns in a closely watched trial that will examine how far prisons can go to ensure security in the age of terrorism.

John Walker Lindh is expected to testify today in Indianapolis during the first day of the trial over prayer policies in a tightly restricted prison unit where he and other high-risk inmates have severely limited contact with the outside world.

Lindh, 31, a Muslim convert who was charged with supporting terrorists after he was captured by U.S. troops in Afghanistan and later pleaded guilty to lesser charges, claims his religious rights are being violated because the federal prison in Terre Haute deprives him of daily group prayer.

Muslims are required to pray five times a day, and the Hanbali school to which Lindh belongs requires group prayer if it is possible. But inmates in the Communications Management Unit are allowed to pray together only once a week except during Ramadan. At other times, they must pray in their individual cells. Lindh says that doesn’t meet the Quran’s requirements and is inappropriate because he is forced to kneel in close proximity to his toilet.

The American Civil Liberties Union of Indiana, which is representing Lindh, contends the policy violates a federal law barring the government from restricting religious activities without showing a compelling need.

“This is an open unit where prisoners are basically out all day,” said ACLU legal director Ken Falk, noting that inmates are allowed to play basketball and board games, watch television and converse as long as they speak English so the guards can understand.

“They can do basically any peaceful activity except praying,” he said. “It makes no sense to say this is one activity we’re going to prohibit in the name of security.”

Joe Hogsett, the U.S. attorney for the Southern District of Indiana, said he believes decisions about prison regulations are best made by prison officials, “not by convicted terrorists and other dangerous criminals who reside there.”

“Mr. Lindh is allowed to pray in his cell; he’s allowed to pray wherever he happens to be as many times every day as his religion suggests to him that he should,” Hogsett said. “Where the rules must draw the line is how often must prison officials allow prisoners to congregate together?”

Attorneys for the government maintain that Lindh’s own behavior since he was placed in the unit in 2007 proves the risks of allowing group prayer.

The government says in court documents that Lindh delivered a “radical, all-Arabic sermon” to other Muslim prisoners in February that was in keeping with techniques in a manual seized from al-Qaida members that details how terrorists should conduct themselves when they are imprisoned.

Lindh’s sermon proves “that religious activities led by Muslim inmates are being used as a vehicle for radicalization and violence in the CMU,” the government claims.

Falk said Lindh’s speech wasn’t radical and was given during the weekly prayer that inmates are permitted. He said Lindh was not disciplined for the speech.

The self-contained unit in which Lindh resides has 43 inmates, 24 of whom are Muslim. Inmates are under open and covert audio and video surveillance, and except for talks with their attorney, all of their phone calls are monitored.