The Branzburg opinion noted that Congress could always enact a statutory privilege. During the 1970s, members of Congress introduced at least 99 bills to do that. But every proposed privilege had exceptions for emergencies and urgent cases; press groups refused to support anything but a blanket privilege. Meanwhile, debates flickered about how a statute should define "journalist." States enacted their own shield laws, until today more than 40 have them -- without much noticeable damage to their law-enforcement efforts.

After the Miller case, members of both parties in Congress tried again. Over a six-year period, three separate Congresses considered bipartisan bills. The proposed legislation would not only have blocked most requests for testimony, but given protection to "third-party" records of news organizations -- like the AP phone records seized by DOJ. One supporter was then-senator Barack Obama. After Obama became president, his administration reversed the Bush Administration's opposition to a statute. In 2010, a proposed shield bill passed the House by unanimous consent, picked up administration support, and seemed headed for passage in the Senate.

Then, in July 2010, Wikileaks unloaded its massive trove of confidential documents about the Afghan war. The drive for a bill came unstuck.

Now it's 2013. The Obama Administration has declared a war on whistleblowers and leaks that dwarfs anything seen since at least the era of Branzburg. I can't fathom why, but that's nothing new. I can't fathom why Obama stonewalled Congress on the Libya intervention; I can't fathom why the Administration is so grudging in explaining the legal basis of the drone war. This vendetta against leakers seems to me beyond all reason.

For people who work for, or talk to, the media, these aren't abstract questions. National security and law enforcement are important, to be sure. But recent history shows that today, just as in the time of John Adams, government officials, with the best of intentions, have a tendency to overreach -- and, when they get away with it, to overreach a bit more.

"Trust us" is bad constitutional theory, and it's leading the administration astray.

Now would be an excellent time for a new debate about First Amendment breathing room for journalists. How broad should it be? How much protection should we offer for phone records and the like? When the government wants to serve a massive secret subpoena for journalist's phone records, might it not be wise to have a court take a look too, rather than the Attorney General, or the Deputy? Do we need a statutory definition of "journalist"?

A statute would be a lot better than the present system. Could it happen?

In 2010, the shield law legislation was co-sponsored by two respected Republicans -- Sen. Richard Lugar and Rep. Mike Pence were both sponsors.

They're both gone. Will current Republicans step up?

Signs aren't good. With crisis swirling around us, the current House calendar centers on a 37th vote to repeal Obamacare. I fear the members will go from there straight to impeachment on one ground or another, bypassing the bothersome law-making phase altogether.