Under fire for secret subpoenas of Associated Press phone records, the Obama administration has asked a key senator to revive legislation that would enhance protections for journalists trying to protect their sources.

A White House official called Sen. Chuck Schumer, D-N.Y., on Wednesday to ask him to reintroduce the media shield law that he supported in 2009 but that never received a vote on the Senate floor. The push comes in the wake of Department of Justice subpoenas of a broad swath of AP's phone records, including several main numbers used by more than 100 reporters.

"This kind of law would balance national security needs against the public's right to the free flow of information. At minimum, our bill would have ensured a fairer, more deliberate process in this case," Schumer said in a statement.

The shield law would insulate journalists from fines and prison time when they refuse to reveal their sources in court cases. It allows journalists to appeal to a federal judge when they don't want to give up their sources to subpoena -- and let the judge decide whether public interest in the journalist's story outweighs the interests of the government.

But the bill also says that in some national security matters, this "balancing test" wouldn't be applied.

That's in part because of White House concerns about the law. In 2009, the White House objected to the shield law's use in national security situations -- like the one the AP believes triggered the secret subpoenas. The wire service reported in 2012 that a double agent had foiled a bomb plot in Yemen.

Attorney General Eric Holder on Tuesday called that leak "a very, very serious leak."

"This is among the top two or three serious leaks that I’ve ever seen," he said.