Plaintiffs challenging the constitutionality of the heavily disputed 2012 National Defense Authorization Act appeared to make some progress during a daylong hearing in a federal court in New York on Thursday.

During the hearing, the U.S. government was unable to clearly define ambiguous phrases in the legislation that critics say could potentially lead to the indefinite detention of journalists and activist groups for exercising free speech.

The class-action lawsuit -- led by Pulitzer Prize-winning journalist Chris Hedges, who was promptly joined by prominent activists such as Noam Chomsky, Daniel Ellsberg, and the Icelandic politician and WikiLeaks defender Birgitta Jonsdottir -- argues that a particular provision written into the broad military-spending bill could effectively lump in political activists and journalists who question government activities as substantial supporters of terrorist organizations.

Buried in the depths of the enormous act is a short paragraph that opponents insist is a drastic threat to Americans' constitutionally protected right to free speech. Section 1021 (b)(2) of the law allows the U.S. military to detain, without a formal charge or a public trial, anyone it suspects has substantially supported al Qaeda, the Taliban, or any other associated forces that may be engaged in hostilities against the United States.

The provision also states those individuals can be detained by military forces until the end of hostilities, a phrase that was particularly disturbing for Hedges, who believes its elusiveness could allow the government to indefinitely hold political dissidents without due process.

The law does not include U.S. citizens, unless they are captured overseas directly supporting terrorist activities. However, opponents fear the language of the statute could eventually be interpreted to apply to all citizens.

The hearing was held to determine if the plaintiffs have grounds to actually pursue a lawsuit against the government. To win the right to sue, at least one of the plaintiffs must establish a reasonable fear of being detained for exercising free-speech rights. If that occurs, those individuals can challenge the law on constitutional grounds.

Journalists Under Threat?

As a veteran war correspondent who has interacted with several terrorist organizations in Central America and the Middle East, Hedges is predominantly concerned with how the NDAA could be used to censor or even target journalists who come in contact with those sources in the course of their reporting.

Under the NDAA, as I see it, if you're writing about something that goes against the official narrative, there is no difference between you and the people you are covering, Hedges said during his testimony on Thursday.

His own experiences as a journalist have compounded his belief that the NDAA could be used to suffocate free speech. While covering the first Gulf War, Hedges said he was detained by military forces for working outside of the official press pool, a detention he attributed to the government's effort to control public perception of the conflict.

Shortly after the 9/11 terrorist attacks in 2001, Hedges said he was detained at Newark Airport while returning to the United States from overseas. He claimed to have heard a member of the airport security team say he was on a watch list. When he questioned them about it, the employees told him they could not discuss the issue, before eventually allowing him to leave the airport.

When pressed by government lawyer Benjamin Torrance about how he could have been included on a watch list, which is typically reserved for suspected or known terrorists, Hedges said he was sure it was for that very reason: because, through his reporting, the government had associated him with terrorism. Under the NDAA, Hedges argued, that would be all the government needed to strip his due-process rights and detain him for an unknown period of time.

Even now, Hedges suspects his phone calls are being monitored. Every time he receives a phone call from Iran, he said it drops after the first ring, a reminder of when El Salvador's government reportedly tapped his phone while he covered the country's gruesome civil war in the 1980s.

Sources associated with groups that the U.S. Justice Department classifies as terrorist organizations have been hesitant to speak with him since the passage of the NDAA, Hedges said. But it goes further than that. Hedges said he himself is reluctant to speak with members of some groups that embrace acts that can be seen as supportive of terrorism.

There is a possibility that people looking at my activity from the outside would not differentiate between myself and someone endorsing that activity, Hedges said, referring to the vagueness of the term associated forces under Section 1021 of the law.

Activist Groups Claim To Be Monitored By Government

Hedges' testimony was preceded by fellow plaintiffs Alexa O'Brien, who co-founded the U.S. Day of Rage, and Kai Wargalla, a member of Occupy London.

O'Brien said her group, a nonviolent association with the goal of reforming the U.S. electoral system, has been monitored by a private intelligence firm that has attempted to link it to Islamic fundamentalists. O'Brien only found out about the monitoring when WikiLeaks released 5 million emails from the geopolitical intelligence firm Statfor, the Courthouse News Service reported.

That was only one of several brushes with the U.S. government O'Brien described in her testimony. Combined with the passage of the NDAA, they have caused her to suspend two investigations she was working on, as an independent journalist, about Guantanamo Bay detainees, for fear of reprisal under the law's indefinite detention provision.

Wargalla echoed those concerns, according to the Courthouse News Service, which said she fears the potential legal ramifications ever since London police reportedly included the local Occupy movement in a memo listing terrorist and extremist groups, alongside al Qaeda and other militant groups.

The author and political activist Naomi Wolf read testimony in court from Jonsdottir, who helped WikiLeaks produce a video of an airstrike by the U.S. military in July 2007 that killed 11 civilians in Baghdad. The video, called Collateral Murder, went viral on the Web.

In her statement, Jonsdottir said she was apprehensive, because she is not a U.S. citizen, about traveling to New York to testify, for fear of being detained under the NDAA.

The remaining plaintiffs -- including Pentagon Papers source Ellsberg, Massachusetts Institute of Technology Professor of Linguistics (Emeritus) Chomsky, and RevolutionTruth founder Jennifer Bolen -- did not testify on Thursday.

Judge, Government Argue Free Speech Is Not 'Heart' Of NDAA Statute

U.S. District Judge Katherine Forrest asked probing questions of both the government and the challengers, although she admitted that she was extremely skeptical that the plaintiffs would be able to prove they have the right to sue.

Because Section 1021 of the NDAA is not specifically about speech -- although she acknowledged it captures speech -- Forrest said she was unsure of whether the plaintiffs' concerns were valid, stating that free speech is not the heart of the statute.

Torrance, representing the government, argued the plaintiffs' concerns are not valid because their fears are based on hypothetical situations. As of now, Torrance said there is no evidence that the NDAA statute in question has limited the free-speech rights of individuals such as reporters, activists, and U.S citizens who have not committed crimes.

The government did not offer any witnesses in support of the law, which it said merely affirms the powers granted under the decade-old Authorization for Use of Military Force. That joint resolution of Congress, passed in the wake of the 9/11 terrorist attacks, granted the president the authority to use all necessary and appropriate force against terrorists responsible for those attacks, as well as against those who harbored such organizations or individuals.

Torrance emphasized the indefinite-detention provision is not intended to limit the First Amendment rights of journalists' or activists' groups, specifically Occupy Wall Street and WikiLeaks. The statute, he said, says the provision applies to terrorist organizations and associated forces, a phrase he said encompasses only those who are in armed conflict against the United States.

However, Carl Mayer, one of the lawyers representing the plaintiffs, said the phrase associated forces is purposely ambiguous, and it can be interpreted to include actions such a political speech as a form of armed conflict. The judge herself questioned the government's inability to define terms such as substantial support and associated forces, asking Torrance how the common citizen is expected to understand its meaning if it could not be defined in court.

The government attorney claimed the phrases in the law that the plaintiffs consider to be vague are defined in previous case law and briefs that outline the executive branch's changing responsibilities.

Hedges told the International Business Times that he believed the plaintiffs presented a stronger case than did the government.

I think the government's argument is surprisingly weak and shot full of holes. The fact that they wouldn't define terms we already said were nebulous really detracts from their position, Hedges said.

Still, Judge Forrest said it would be difficult for her to reconcile finding [the statute] unconstitutional. She said she is bound by the U.S. Surpreme Court's decision in Holder v. Humanitarian Law Project to tread carefully when dealing with laws concerning national security.

The plaintiffs and defendants must submit written arguments to the court in April. Forrest will then decide if the case can move forward.