When news broke in late January that James O’Keefe and three other men, two of whom were costumed as telephone repairmen, had been arrested by federal authorities and charged with “interfering” with the phone system at the New Orleans office of Sen. Mary Landrieu, observers of all sorts shared a similar response: What were they thinking?

Thanks to a statement O’Keefe has posted at Andrew Breitbart’s BigGovernment.come and an interview he gave Monday night to Fox News’s Sean Hannity, we now have a pretty good answer to that question. Landrieu had drawn the ire of some conservatives for her participation in a deal that helped advance health care reform, and the anger had grown amid claims that her office was avoiding calls from constituents. O’Keefe told Hannity:

We wanted to get to the bottom of the claim that [Landrieu] was not answering her phones, her phones were jammed. We wanted to find out why her constituents couldn’t get through to her. We wanted to verify the reports.

And while O’Keefe has acknowledged that, “on reflection, I could have used a different approach to this investigation,” he also told Hannity he was operating in an established tradition: “We used the same tactics that investigative journalists have been using. In all the videos I do, I pose as something I’m not to try to get to the bottom of the truth.” During the interview, he and Hannity name-checked a few specific predecessors, among them PrimeTime Live’s Food Lion investigation, 60 Minutes, 20/20, and Dateline NBC, including its “To Catch a Predator” series.

Considering the extent to which O’Keefe’s activities are driven by political goals, it’s debatable whether or not he really belongs to this family tree. But even taking him at his word, lumping O’Keefe in with those programs doesn’t necessarily put him on the safe ground he’s looking for. Journalism ethicists have long been wary of deceptive undercover tactics that those programs (and others) use—and with good reason. Overreliance on sting operations and subterfuge can weaken the public’s trust in the media and compromise journalists’ claim to be truth-tellers. Undercover reporting can be a powerful tool, but it’s one to be used cautiously: against only the most important targets, and even then only when accompanied by solid traditional reporting.

The field’s squeamishness with “lying to get the truth,” as the headline of a 2007 American Journalism Review article put it, is well-documented. In the 1970s, the Chicago Sun-Times set up an elaborate sting operation at the Mirage Tavern to document routine corruption in city agencies; the sting worked, but the paper’s Pulitzer hopes were dashed, reportedly because Ben Bradlee and Eugene Patterson disapproved of its methods. PrimeTime Live’s decision to have producers falsify resumes and smuggle hidden cameras into a Food Lion grocery store sparked contentious litigation (an initial $5.5 million jury verdict against ABC was reduced on appeal to $2) and drew two articles in CJR (not online).

Most recently, Ken Silverstein, the acclaimed Washington editor of Harper’s, posed as a foreign businessman to expose lobbyists’ willingness to represent unsavory clients. Silverstein came back with a gripping story and had plenty of defenders, but institutions like the Center for Public Integrity sided with The Washington Post’s Howard Kurtz in criticizing his methods.

In other words, press criticism of O’Keefe may reflect ideological disagreement in some cases. More broadly, it no doubt reflects some schadenfreude from an institution he and his patron Breitbart have conspicuously disdained. But it’s also consistent with the wariness with which much of the media—especially the print media—has long viewed undercover reporting.

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.”)

Greg Marx is an associate editor at CJR. Follow him on Twitter @gregamarx.