A federal judge is blocking legislation authorizing the government to indefinitely detain without trial an "individual who was part of or substantially supported" groups "engaged in hostilities against the United States or its coalition partners."

Tuesday's decision by a New York federal judge halts a key terror-fighting feature of the 2011 National Defense Authorization Act and is a blow to the Obama administration. The government urged U.S. District Judge Katherine B. Forrest not to adopt a nationwide ban on the measure, saying the move would be "extraordinary" and "unwarranted" (.pdf).

But the judge, ruling in a case brought by journalists and political activists, said the law was too vague and did not provide clear guidance on whom the government could indefinitely detain.

Last month when Judge Forrest granted standing to the plaintiffs based on their fears of being detained for their writing and political activism, she wrote (.pdf) that, "Before anyone should be subjected to the possibility of indefinite military detention, the Due Process Clause of the Fifth Amendment requires that individuals be able to understand what conduct might cause him or her to run afoul of" the statute.

And on Tuesday, in a follow-up ruling (.pdf), she said her blockage of the law applied nationwide, not just to the plaintiffs, who include Pulitzer Prize-winning journalist Christopher Hedges and WikiLeaks activist Brigitta Jonsdottir.

The Obama administration had argued that the judge's original decision only applied to the plaintiffs, an interpretation the judge ruled Tuesday was false.

The plaintiffs maintain the law has chilled their speech and fear their activities could subject them to military detention. "Unfortunately, there are a number of terms that are sufficiently vague that no ordinary citizen can reliably define such conduct," the judge wrote.

Those subject to indefinite detention under the National Defense Authorization Act include:

A person who was part of or substantially supported al-Qaeda, the Taliban, or associated forces that are engaged in hostilities against the United States or its coalition partners, including any person who has committed a belligerent act or has directly supported such hostilities in aid of such enemy forces.

The plaintiffs argued that the law was so vague that simply having contact with and reporting on organizations labeled as "terroristic" by the government would be grounds for indefinite detention by the government.

The act is a broad package of legislation that also includes both authorizations for military spending as well as additional, non-spending legislation. In his Dec. 31 signing statement, President Barack Obama said that "my administration will not authorize the indefinite military detention without trial of American citizens."

But the statement didn't sway Judge Forrest.

"This Court is acutely aware that preliminarily enjoining an act of Congress must be done with great caution," the judge wrote. "However, it is the responsibility of our judicial system to protect the public from acts of Congress which infringe upon constitutional rights. "

Photo: CoDiFi/Flickr