Senators began a new effort to pass a media shield law Thursday, re-introducing legislation they said would protect journalists from being sent to jail for refusing to reveal their sources in most cases.

The bill, re-written with guidance from more than 30 news organizations including The Associated Press, drew new support after changes that could force reporters to disclose sources if they witnessed a crime or obtained information deemed secret by law.

"There has been a deadlock on improving the shield law for the very reason that not all disclosures by government officials to members of the press are equal," said Sen. Charles Schumer, D-N.Y., announcing he was supporting the bill for the first time.

"We need to protect the press, especially with a big, large government that keeps things secret more and more," Schumer added. "We also have to have some respect for the fact that there are certain things that shouldn't be made public by statute."

Some lawmakers remained skeptical about shielding reporters in wartime.

Sen. Jeff Sessions, R-Ala., said he was chilled by the awards of high journalism honors this year to reporters who revealed the CIA's use of secret prisons overseas and the National Security Agency's tapping of domestic phone calls and e-mails without court warrants.

"If a spy comes into our country and gets secure information and gives it to our enemy, we prosecute them and put them in jail," Sessions said. "But if a reporter gets information and publishes it to our enemies and to the whole world, they get the Pulitzer Prize."

"I think we need to be a little bit careful how we'll word this," he added.

Aware that the old version had almost no hope of becoming law, Senate authors Richard Lugar, R-Ind., and Arlen Specter, R-Pa., added new shield exceptions they said were modeled on Justice Department guidelines.

One would require reporters who are eyewitnesses to crimes to disclose the information. Others would remove the shield if disclosure was critical to preventing death or bodily harm.

Journalists or their employers also would be required to disclose information needed to prevent an act of terrorism or harm to national security.

The exception for national security also requires a court to apply a balancing test in which "the value of the information that would be disclosed clearly outweighs the harm to the public interest and the free flow of information that would be caused by compelling the disclosure."

Prosecutors also could trigger the exception if they could convince a court an unauthorized disclosure of classified information "has seriously damaged the national security ... (and) the harm caused by the unauthorized disclosure of properly classified government information clearly outweighs the value to the public of the disclosed information," according to the bill.

The legislation more tightly defines "journalist" by excluding writers who do not provide regular news coverage, such as occasional Internet bloggers.

The next step is consideration by the Senate Judiciary Committee that Specter chairs. No companion bill has been introduced in the House.

The rewritten bill was inspired in part by the incarceration of journalist Judith Miller, then of The New York Times, last year for refusing to testify about a source in the investigation into the leaking of the identity of former CIA agent Valerie Plame.

The Justice Department did not immediately respond to a request for comment. Last year, Chuck Rosenberg, a U.S. attorney in Texas, told Specter's panel that current department guidelines do not put the First Amendment and its guarantee of freedom of the press under assault.

Rosenberg said that in the past 15 years 12 of 243 subpoenas issued under Justice Department guidelines to news media called for confidential source information.

"We seek information about confidential sources from reporters only when it really, really matters," Rosenberg testified last October.