“What you wouldn’t gather” from the coverage at major newspapers, media watchdog Jim Naureckas pointed out, “is that there is a long and honorable tradition, from Nellie Bly feigning madness to expose mistreatment of the mentally ill to the Chicago Sun-Times’ Mirage Tavern corruption lab, of investigative journalists using false identities to gather information—when the public interest is clear, and there’s no other way to get the story.” Naureckas noted a couple of other famous examples. In 1992, ABC News reporters used false identities to get jobs at a Food Lion grocery store and secretly film improper food-handling practices. In 2007, Harper’s Ken Silverstein’s impersonated a fictitious representative of Turkmenistan to trick a couple of Washington, D.C. lobbying and communications firms into pitching PR plans that he described as an effort to bolster the image of a dictatorial government.

Deceptive tactics and undercover reporting have steadily lost favor over the decades, however. Despite the fact that Sun Times’ Mirage Tavern sting exposed rampant corruption among city inspectors who took bribes to ignore a variety of flagrant safety violations, and led to widespread reforms, it failed to win a Pulitzer because of accusations that it violated journalistic ethics. Food Lion successfully sued ABC for breach of loyalty and trespassing. And some critics called Silverstein’s tactics unprofessional. (For two excellent histories of the rise and fall of deceptive tactics, which have been more common on television than in print, see the American Journalism Review’s 1997 article, “The Lying Game,” and its 2007 article, “Lying to Get the Truth.”)

Beyond this historical context, what’s been missing from the debate about Gleick’s actions is a closer examination of the legal questions a journalist must take into account when weighing deceptive tactics.

Gleick leaked information to the press, which puts him in league with figures like Daniel Ellsberg, the source of the Pentagon Papers, and Bradley Manning, the source of the Wikileaks cables, rather than with the muckraking journalists of yore. As such, the websites that received them in an anonymous e-mail and decided to publish them are fairly well protected by the 2001 Supreme Court case, Bartnicki v. Vopper, which established that media outlets are basically free to use information “of public concern” provided by third parties, even if it was illicitly acquired, as long as they did not encourage or play a role in the illicit acquisition.

The fact that Heartland said one of the leaked documents was a fake adds some element of legal risk, but not an insurmountable one, according to Lee Levine, who represented the media defendants in Barnicki v. Vopper:

There’s no law that says it’s illegal to post a fake document or to disseminate a fake document. Now, it is conceivable that if the documents made The Heartland Institute look bad and contained accusations that were defamatory about it, the rules that cover defamation law would apply and Bartnicki would have nothing to do with it. And the rules that govern defamation law are that if the plaintiff is a public figure—and more often than not a corporate entity or large institutional entity like that would be a public figure—they would have to prove that the poster either knew that information in the document was false or acted in reckless disregard of whether it was false or not.

It’s a principle otherwise known as “actual malice.” Failure to call Heartland to verify the strategy memo would be unlikely to constitute reckless disregard, Levine and several other legal experts agreed. “Unless there was something about the document that would cause them to question whether it was accurate, they would have no obligation to go and independently try to check it out—legally,” he said. “Journalistically is an entirely different matter.”

Curtis Brainard is the editor of The Observatory, CJR's online critique of science and environment reporting. Follow him on Twitter @cbrainard.