Nicholas George was detained for five hours at an airport more than four years ago for carrying Arabic-English flashcards, but a judge has ruled the agents responsible cannot be sued.

According to Reuters, the Third U.S. Circuit Court of Appeals in Philadelphia overturned a ruling in a lower court. George was detained Aug. 29, 2009 in Philadelphia International Airport for having Arabic-English flashcards with words like "terrorist" and "bomb" printed on them.

The judge's decision stated the three Transportation Security Administration (TSA) and two FBI agents acted with qualified immunity in the situation. Essentially, the judge ruled George's five-hour detention was lawful.

The ruling will not affect an existing case against the federal government and against the Philadelphia police officer who handcuffed George early in the detention.

George said the flashcards were meant to help him understand Middle Eastern media as well as a book critical of U.S. foreign policy. 21 at the time, George was traveling back to Pomona College in Calif. for his senior year. He was student with a double major in physics and Middle Eastern studies.

While in detention, George said he was asked if he knew "who did 9/11" and what language Osama bin Laden spoke.

The initial decision to allow George to pursue a lawsuit came from a lower court in Oct. 2011, with the judge ruling the agents violated the young man's First and Fourth Amendment rights. Writing for a three-judge panel for Philadelphia's Third Circuit Court of Appeals, Chief Judge Theodore McKee reasoned, "in a world where air passenger safety must contend with such nuanced threats as attempts to convert underwear into bombs and shoes into incendiary devices."

The decision reversed the lower court's ruling, but agreed that George's First Amendment rights absolutely allowed him to have the cards. Still, the new decision said the TSA and FBI agents acted lawfully in their detention.

"It is simply not reasonable to require TSA officials to turn a blind eye to someone trying to board an airplane carrying Arabic-English flashcards with words such as 'bomb,' 'to kill,' etc," McKee wrote. "Basic common sense would allow those officials to take reasonable and minimally intrusive steps to inquire into the potential passenger's motivations."

George's representative, Ben Winzer, an attorney for the American Civil Liberties Union, told Reuters his client may appeal and will pursue his other existing cases.

"It is hard to determine, from reading this opinion, what materials might subject travelers to detention against their will," Wizner said. "The court does not explain how possession of Arabic-English flashcards by a college student gives rise to any suspicion, much less reasonable suspicion."