At stake in the legal fight -- beyond placing criminal responsibility for thousands of classified U.S. documents being posted on the Internet -- is how much privacy Twitter and other social network users can expect or whether such messages are considered private at all.
The American Civil Liberties Union and the non-profit Electronic Frontier Foundation went to court in Alexandria, Va., last week to try to stop the government's acquisition of the Twitter messages.
An Assange lawyer said earlier an array of social networks, not just Twitter, was being mined by the government for information.
Ironically, the Alexandria hearing occurred on the same day President Barack Obama was publicly telling autocratic governments: "The world is changing … with a young, vibrant generation within the Middle East that is looking for greater opportunities. If you're governing these countries, you've got to get ahead of change; you can't get behind the curve."
Twitter and other forms of Internet social networking are given credit both for generating protests and keeping protesters in touch with each other. In Egypt and Tunisia, it led to regime change. Demonstrations inn Iran, Yemen, Bahrain and elsewhere are continuing.
On the same day, Secretary of State Hillary Clinton was giving a speech advocating the freedom of the Internet. She told a crowd at The George Washington University in Washington: "Egypt isn't inspiring people because they communicated using Twitter. It is inspiring because people came together and persisted in demanding a better future. Iran isn't awful because the authorities used Facebook to shadow and capture members of the opposition. Iran is awful because it is a government that routinely violates the rights of its people."
Meanwhile, the U.S. Justice Department was in federal court in Alexandria trying to obtain Twitter messages to build up its WikiLeaks criminal case.
The ACLU and EFF earlier filed three motions before U.S. Magistrate Judge Theresa Buchanan: A request to overturn a Dec. 14 court order forcing Twitter and possibly others to turn over the private records of some users a request to unseal court records about the government's attempts to collect those private records through subpoenas and, finally, a request to unseal the original two motions and the hearing initially sealed by the court.
Buchanan granted the motion to unseal and heard argument last Tuesday on the other two motions.
The ACLU and EFF filed the motions on behalf of Birgitta Jonsdottir, a member of Iceland's Parliament. Private lawyers represented WikiLeaks associates Jacob Applebaum and Rop Gonggijp. CNN said the three are believed to have helped prepare a classified U.S. Army video published last year on the WikiLeaks Web site.
But the twists of the case also include trying to find a connection between Assange and U.S. Army Pfc. Bradley Manning, a former intelligence specialist in Iraq now cooling his heels in the Marine Corps brig in Quantico, Va.
U.S. officials say Manning downloaded tens of thousands of classified documents while in Iraq and then presented them to WikiLeaks. How they were presented is part of the problem. WikiLeaks was designed to allow users to upload material on their own without help by site operators.
Pentagon officials familiar with the investigation have said U.S. investigators so far have been unable to link Assange to Manning, McClatchy Newspapers reported earlier this month.
On its Web page, EFF said last Tuesday's hearing only came about because Twitter notified its users that the government was seeking the information.
The privacy group and the ACLU argued in part that the attempts to get Twitter messages violated the Fourth Amendment's ban on unreasonable searches because the messages would reveal the location of the computers on which they were sent, and the government hasn't demonstrated the need for such information.
Moreover, EFF said, "The issues at hand -- WikiLeaks, privacy, free speech and social networking -- are all important matters of public interest, and the orders and motions before the judge should be available to inform public debate."
Aden Fine, ACLU staff attorney for the Speech, Privacy and Technology Project and the ACLU's lead attorney at the Alexandria hearing, said, "We tried to make our point, which is that the government should not be able to get this information and above all they should not get this information in secret.
"That's not how our system works and it shouldn't be permitted here," he said by telephone from New York. "There are certain things that one does on Twitter that are public. The information that the government is seeking is by definition non-public information. ... Everything that they're seeking is non-public information. … and the information that they're seeking will reveal private details about one's activities and associations."
On the other side, Assistant U.S. Attorney John Davis argued, "Tweets are public statements," CNN reported. Magistrate Buchanan seemed to agree, saying, "There is no expectation of privacy when using Twitter."
She promised to rule soon on the ACLU and EFF motions.
The Alexandria hearing is part of the larger legal dispute involving WikiLeaks founder and operator Assange and whether he should be prosecuted under the 1917 Espionage Act or under some other U.S. law.
Assange released what he said were about 75,000 documents on the Afghan War last July, offering prime media an early look at the material. He had been in the process of releasing about 250,000 U.S. State Department cables this fall and winter before becoming entangled in unrelated legal problems in Sweden.
Assange, an Australian national, is currently under house arrest in England awaiting a ruling on extradition to Sweden to face sexual assault charges.
Meanwhile, in a classic case of closing the barn door once the horse has gone up the road, the White House Dec. 5 ordered all federal employees and military service members not to look at WikiLeaks.
"Classified information, whether or not already posted on public Web sites or disclosed to the media, remains classified, and must be treated as such by federal employees and contractors, until it is declassified by an appropriate U.S. government authority," the White House said. "Viewing or downloading still-classified documents from unclassified government computers creates a security violation."
The controversy evokes considerable critical comment in the United States, both of Assange's actions and a possible U.S. prosecution.
U.S. Sen. Joe Lieberman, Ind-Conn., has called not only for the prosecution of Assange and WikiLeaks, but an investigation of publications such as The New York Times that used some of WikiLeaks' postings.
But Human Rights Watch, in a letter to Obama last December, said prosecuting Assange would be a "terrible precedent."
"Prosecuting WikiLeaks for publishing leaked documents would set a terrible precedent that will be eagerly grasped by other governments, particularly those with a record of trying to muzzle legitimate political reporting," Dinah PoKempner, a lawyer at Human Rights Watch, said.
The WikiLeaks dispute, like its spiritual predecessor the Pentagon Papers in 1971, may eventually reach the halls of the U.S. Supreme Court.