There are practical reasons for that wariness. As other observers have noted, while the use of deception in reporting can yield sensational results, it also lends the subject a weapon to wield against the journalist. The ready-made complaint: If the reporter has forfeited the high ground of transparency and honesty, how can his conclusions be trusted by the public? The fallout may not be limited to the case at hand. During the Food Lion controversy, Marvin Kalb of Harvard’s Shorenstein Center worried that widespread use of deception “demeans journalism and damages badly the journalist and the public.” (This is not a theoretical problem. In announcing the verdict in the Food Lion case, the jury foreman told ABC, “You didn’t have boundaries when you started this investigation…. You kept pushing on the edges and pushing on the edges…. It was too extensive and fraudulent.”)

To mitigate this concern, undercover reporters are urged take care to situate what they’ve gleaned through deception in a structure of traditional reporting—to show that, unlike, say, Punk’d or Candid Camera or even “To Catch a Predator,” the gimmick is not all there is. Wherever one comes down on Silverstein’s work, one of the more effective criticisms of it was that his original story never gave the lobbying firms he targeted an opportunity to comment. A similar criticism applies to O’Keefe’s ACORN videos, which made him a national figure—whatever malfeasance he may have uncovered at ACORN, his failure to present his videos in any broader reportorial context made it difficult for the national media to take his allegations seriously. (And when other journalists did look into the story, they found that the footage, while containing some truly troubling material, should not all be taken at face value.)

That’s not the only guideline for going undercover. While there are, appropriately, no hard-and-fast rules or central authorities for journalism, a checklist drawn up by Poynter’s Bob Steele in 1995 is often cited for guidance on this issue. A few points on the list are probably too vague to be of much use, but the first two are valuable. They state that deception and hidden cameras may be appropriate:

When the information obtained is of profound importance. It must be of vital public interest, such as revealing great “system failure” at the top levels, or it must prevent profound harm to individuals.

When all other alternatives for obtaining the same information have been exhausted.

Whether something is of “profound importance” is obviously a matter of news judgment, but there’s good reason to question O’Keefe’s. If his focus on ACORN was the product of a worldview that vastly exaggerated that group’s practical political importance, his decision that Landrieu’s phone system merited a hidden-camera investigation was even more off the mark.

Public officials should be responsive to their constituents, and when credible concerns are raised that they aren’t, the press should check them out. (In fact, as this story by Alexandra Fenwick notes, reporters in Louisiana did look into those allegations, and managed to do so without resorting to costumes or cell phone cameras.) But even if O’Keefe’s suspicions about Landrieu turned out to be true, her actions would count as little more than a good-government misdemeanor. Deciding that they warranted undercover treatment is a reflection of editorial judgment unconstrained by common sense.

Of course, O’Keefe’s comment to Hannity—“In all the videos I do, I pose as something I’m not”—suggests that he skipped this balancing test entirely. Attempts to reach O’Keefe for comment were unsuccessful, but in an interview late Wednesday night Breitbart defended his approach. “My tactics are unorthodox, and his tactics are unorthodox, because the mainstream media is full of shit,” he said. “When we report the truth, you ignore it.” Later, he added, “You guys are creating the market for creative journalism—it wouldn’t be there if you guys did your job.” (Whatever the merits of this argument, it is not exactly the defense that O’Keefe has advanced.)

Greg Marx is a CJR staff writer. Follow him on Twitter @gregamarx.