The House of Representatives has approved legislation intended to block federal prosecutors from forcing journalists to testify about their work. But there’s disagreement among experts on what the one-sentence spending amendment means.

Critics who believe the wording is too broad say it would allow virtually anyone to avoid testifying in federal criminal cases. Others say it might not prove useful to journalists or anyone else.

The amendment, adopted Wednesday in a 245-182 vote, was tacked onto a multiagency spending bill that allocates funds for fiscal 2016 to the Department of Justice. The provision says:

"None of the funds made available by this Act may be used to compel a person to testify about information or sources that the person states in a motion to quash the subpoena that he has obtained as a journalist or reporter and that he regards as confidential.”

Joel Kurtzberg, an attorney who represented New York Times reporter James Risen in a multiyear fight against testifying at the leak trial of former CIA officer Jeffrey Sterling, says the wording is too broad.

“If this became law, it would provide significantly needed protection to journalists who need to be able to keep their promises to confidential sources in order to do their jobs,” he says. “The difficulty with it, however, is that it appears to provide protection for anyone who claims in motion papers to have obtained confidential information as a journalist."

Kurtzberg says if the amendment passes the Senate and becomes law anyone who claims to be a journalist could be off the hook from testifying.

“There is no mechanism built in for the courts to evaluate the validity of any such claim,” he says. “Anyone who states that meets the test [and] that doesn’t mean it’s a valid claim.”

Barry Pollack, an attorney who represents WikiLeaks publisher Julian Assange as well as Sterling, who was convicted in January without Risen’s testimony, holds a very different opinion.

Pollack says the amendment may in some cases extend no protection to journalists. Judges, he says, would still have to rule on motions to quash subpoenas, even if federal prosecutors are prevented from filing a reply.

“I wouldn't say it offers no real-world protection,” he says. “It offers limited and imperfect protection. It would constrain what the Department of Justice could do. Anyone has a better chance if the opponent has one arm tied behind its back. But it is the referee, not the opponent, who makes the decision.”

Federal law, he points out, does not currently recognize a reporter’s privilege to protect confidential sources, meaning judges could still compel reporter testimony with the threat of jail time for refusal.

“Unless the law changes, judges may continue to rule against journalists, even without the Department of Justice openly advocating for that result,” Pollack says.

The amendment’s author, Rep. Alan Grayson, D-Fla., tells U.S. News the amendment is “an entirely practical” proposal that would, in his view, have a real impact.

Though he would prefer that Congress pass permanent reporter protection legislation, Grayson believes the spending prohibition would be favorably and reasonably interpreted by courts. Judges and juries, he says, make more complicated decisions “a million times a day.”

Grayson points to former House Speaker Dennis Hastert’s recent indictment for allegedly lying to the FBI when asked if non-journalists could misuse the provision.

“If you go to court and lie about anything, or lie to federal agents ... then that itself is a crime and will lead to you being in prison,” he says.

Grayson is optimistic the 63-vote margin of victory in the House means the amendment has a good shot in the Senate, where he intends to lobby “defenders of freedom” to sponsor identical legislation.

Last year, a similar measure passed the House in a more narrow 225-183 vote and was not acted upon by the then Democrat-controlled Senate. An omnibus spending bill negotiated by congressional leaders omitted the amendment last year, but Grayson believes the now-Republican-led Senate’s apparent preference to pass individual spending bills may assist his effort.

The Supreme Court ruled in 1972 journalists have no constitutional right to privileged communication with sources. “Congress has freedom to determine whether a statutory newsman's privilege is necessary and desirable and to fashion standards and rules as narrow or broad as deemed necessary,” the justices wrote in Branzburg v. Hayes. The court has thus far declined to revisit the ruling, most recently turning down an appeal from Risen last year.

The threat of jail isn’t always hypothetical for reporters who wish to keep promises to their sources. In 2005 journalist Judith Miller, then with The New York Times, was jailed 85 days for refusing to identify a source during controversy over the public naming of CIA agent Valerie Plame.

“If [Congress] can get this done by tying up funding I have no problem with that,” Miller says. “I just want the protection.”

But Miller, now a Fox News contributor and Manhattan Institute fellow, says she’s not optimistic the amendment will pass the Senate. And she’s even less hopeful the Obama administration will soften its aggressive pursuit of leaks through reporters who publish them.

“This administration has scared the bejesus out of people and they don’t want to talk to us -- even those of us who have gone to jail,” she says. President Barack Obama, she adds, “is very much an information control freak, he doesn’t like the media [and] a lot of reporters for too many years thought of themselves as part of his administration.”

Many state legislatures have passed laws shielding reporters from testifying in state courts, but Congress has gone decades without passing federal legislation. A Senate committee passed a media shield bill in 2013 that controversially defined journalists in a way that would exclude Assange, the famous secret publisher, from protection. The bill, backed by the Obama administration, was unsuccessful.

House Judiciary Committee Chairman Bob Goodlatte, R-Va., spoke against Grayson’s amendment this week, saying the wording was too broad. "Shield laws for reporters are not a bad concept at all, but this is hardly the way to go about doing it," he said.