I'm still looking for more definitive legal reference, but here is the "layman's" version of the relevant argument. Glantz received an anonymous package of internal tobacco company documents and published them. Then, as described in the profile above:
When Brown & Williamson filed suit to force the return of the documents in February 1995, the stage was set for a First Amendment fight. Suddenly, the very freedom of a researcher and a university to disseminate information was on the line. "Basically, they were trying to keep books out of the library, and universities are here to spread information, not suppress it," Glantz says. He was summoned to a meeting at the university counsel's office, across Parnassus Avenue, which runs through the UCSF campus. "I was riding the elevator down and I was thinking, 'Time to walk the plank. They're going to toss me overboard.'"
But saying they'd rather fight than quit, the UC administrators backed Glantz. The university lawyers argued that the documents were a legitimate subject of study and that they were already public records because they had been written about so extensively in the New York Times and elsewhere. In June 1995, the California Supreme Court ruled in the university's favor. To spare strain on the library, the university published them on the Internet and sold copies on CD-ROM.
In the case of the Diebold memos, these documents have been extensively published on the web (see citations at http://www.why-war.com/features/2003/10/diebold.html) and elsewhere, including a book and at least one widely-syndicated AP article. More coverage will surely follow. I think the precedent holds.