In today's Guardian, Glenn Greenwald writes:

The Obama White House's extreme fixation on secrecy is shaped by a bizarre paradox. One the one hand, the current administration has prosecuted double the number of whistleblowers - government employees who leak classified information showing high-level official wrongdoing - than all previous administrations combined. Obama officials have also, as ACLU lawyers documented this week in the Guardian, resisted with unprecedented vigor any attempts to subject their conduct to judicial review or any form of public disclosure, by insisting to courts that these programs are so secretive that the US government cannot even confirm or deny their existence without damaging US national security.

But at the very same time that they invoke broad secrecy claims to shield their conduct from outside scrutiny, it is Obama officials themselves who have continuously and quite selectively leaked information about these same programs to the US media. Indeed, the high publicity-value New York Times scoops of the past two weeks about covert national security programs have come substantially from Obama aides themselves.

...
In sum, these anonymous leaks are classic political propaganda: devoted to glorifying the leader and his policies for political gain. Because the programs are shrouded in official secrecy, it is impossible for journalists to verify these selective disclosures. By design, the only means the public has to learn anything about what the president is doing is the partial, selective disclosures by Obama's own aides - those who work for him and are devoted to his political triumph.

But that process is a recipe for government deceit and propaganda. This was precisely the dynamic that, in the run-up to the attack on Iraq, co-opted America's largest media outlets as mindless purveyors of false government claims. The defining journalistic sin of Judith Miller, the New York Times' disgraced WMD reporter, was that she masqueraded the unverified assertions of anonymous Bush officials as reported fact.
...
Perhaps the most pernicious effect of this type of journalism is that it converts journalists into dutiful messengers of official decrees. Reporters are trained that they will be selected as scoop-receivers only if they demonstrate fealty to the agenda of official sources.

In the article, Greenwald gives two examples of the difference in how two NYT journalists are treated when one writes glorifying articles on successful government missions and the other points out the mistakes.

I don't think they need to amend that ban on domestic dissemination of propaganda. They've already figured out how to spread government misinformation.