Last week, I submitted an affidavit to support an important lawsuit brought by reporter Chris Hedges and others, including Daniel Ellsberg and Noam Chomsky, against U.S. President Barack Obama and his defense secretary, Leon Panetta.

The lawsuit seeks to stop implementation of the horrific new National Defense Authorization Act, also known as the “Homeland Battlefield Bill,” which Obama signed into law in December. As a result, the United States government’s “war on terror” has come home: Any American may now be detained indefinitely, without charge or trial, anywhere, at any time, forever.

As Hedges wrote recently in a chilling explication of why he is bringing the lawsuit, the NDAA’s “crucial phrases are ‘substantially supported’ and ‘associated forces.’” These two phrases, he argues, allow the government to expand the definition of terrorism to include groups that were not involved in the terrorist attacks of Sept. 11, 2001, and that may not even have existed when those attacks took place. According to Hedges, “the law can be used to detain individuals who are not members of terrorist organizations but have provided, in the words of the bill, substantial support even to ‘associated forces.’”

As Hedges points out, neither of these terms is properly specified, nor does the law define an act of terror, or the activities of those purportedly “engaged in hostilities against the United States.” As Hedges puts it, “this is why, especially as acts of civil disobedience proliferate, the NDAA law is so terrifying.”

He is absolutely right, and his deposition details how the NDAA and similar legislation is being used to obstruct his investigations and intimidate him personally. He describes being detained by U.S. officials while reporting overseas, and being advised that he is on a watch list. He also understands, as few U.S. reporters do, how similar legislation has been used to terrorize and intimidate reporters in other countries.

Hedges, a former reporter for The New York Times, witnessed this in El Salvador. But almost identical laws have been used to impede reporting and news publishing, and to harass, intimidate, and even imprison journalists, in fascist Italy, in early Nazi Germany, in the former Soviet Union, and under military rule in Chile, Argentina and Ecuador.

On March 29, I joined supporters of the lawsuit in a New York City courtroom to determine if the plaintiffs would be granted legal standing to challenge the government’s planned actions. Katherine O’Brien, another journalist, detailed her own intimidation by a self-identified Federal agent, and the co-founder of Occupy London, Kai Wargalla, produced a memo from the London Police categorizing her group as “terrorists.”

The hearing’s crescendo was tough questioning of the government’s lawyers by Federal Judge Katherine B. Forrest, who repeatedly asked the government’s lawyers to define the terms “substantially supported” and “associated forces,” a request that was unanswered, despite restating her question seven or eight times.

Forrest also repeatedly asked for assurances – at least five times – that the NDAA would not sweep up people like the plaintiffs: journalists engaged in journalism and citizens engaged in peaceful protest. Again, every time, the lawyers for Obama and Panetta said that they could not give her such assurances. At the end of April, the two sides will present new briefs, and she will announce the next stage of the process after she deliberates over the new material.

We now have it from the U.S. government lawyers’ own mouths: This law may put journalists at risk, or at least the lawyers explicitly refused to rule out that option for their client – and, as Forrest put it, they have “one very big client.”

Vaguely defined terms are a standard part of the totalitarian toolkit, and they always begin, as Hedges notes, with legislation that subverts the rule of law by enabling the arbitrary exercise of power. Such terms always ensnare, early on, reporters, editors and newspaper publishers with threats that they are jeopardizing “national security” or, by reporting on them, showing “support” for outlawed and nefarious forces.

My own affidavit agrees with Hedges’ argument that U.S. reporters are already modifying their behavior in response to such laws – and to frightening recent examples that have been made of controversial publishers like WikiLeaks’ Julian Assange. I detail examples of stories that I myself did not pursue because of the official intimidation that these laws represent: a decision not to meet with released Guantanamo prisoners in London, or to showcase fundraising for an important documentary about the bombardment of civilians in Gaza.

There was also a very painful recent decision – legally unavoidable but one that made me feel, as a journalist, dishonorable and ashamed – not to pursue a proposed face-to-face encounter with Assange while he was under house arrest near Cambridge.

I know that many other U.S. reporters are making similar decisions as a result of the NDAA, and I hope that they join this lawsuit whether with affidavits of their own, or as plaintiffs. Such laws make otherwise conscientious reporters hesitate to do what is professionally right.

It is not just American reporting that suffers when a law such as the NDAA threatens journalists and editors. With U.S. legislation and claims of executive authority increasingly giving U.S. presidents the power to wage wars, declare all of America a battlefield, assassinate U.S. citizens and non-citizens around the world, hold Afghanis, Iraqis and Pakistanis indefinitely without charge or trial, and accuse Australian publishers of espionage, the rest of the world needs fearless and accurate American reporting. That is the first step toward holding U.S. leaders accountable under domestic and international law. Unfortunately, such accountability is needed now more than ever.

Naomi Wolf is a political activist and social critic whose most recent book is “Give Me Liberty: A Handbook for American Revolutionaries.” THE DAILY STAR publishes this commentary in collaboration with Project Syndicate © (www.project-syndicate.org).