WASHINGTON -- A day before Congress weighs an amendment to end indefinite military detentions in the U.S., a federal judge Wednesday ruled the law that allows the practice unconstitutional.

Saying the measure has "chilling impact on First Amendment rights," U.S. District Judge Katherine Forrest, of New York's Eastern District, found that a group of reporters and activists who brought the lawsuit had no way of knowing whether they could be subjected to it. That makes it an unconstitutional infringement on the First Amendment's free speech right and the Fifth Amendment's right to due process, Forrest said in a written opinion.

The lead plaintiffs -- Pulitzer Prize winner Chris Hedges of the Nation Institute and Tangerine Bolen, who runs the website RevolutionTruth -- argued that they conceivably could be grabbed under the law because they deal with sources that U.S. authorities may deem to fall under the law, Section 1021 of the 2012 National Defense Authorization Act.

The law defines the suspects who can be detained as a "person who was a part of or substantially supported al-Qaeda, the Taliban, or associated forces."

Forrest found the language too vague, and repeatedly tried to get government attorneys to say that the reporters' fears were unfounded. The lawyers declined.

Homeland Battlefield Act Portion Found Unconstitutional By New York Judge