What is a reporter’s obligation to shed light for readers on the sources of the opposition research they use in their work? “I think it probably depends on the circumstances,” says Edwin Chen of the Los Angeles Times. “If the Bush campaign said, ‘Gee, Chen, you should go look at a speech John Kerry made on such and such a date in the Senate,’ and I look it up, I don’t need to [tell readers], ‘I was pointed to this by the Bush campaign.’ If it’s hard-to-get information that cannot be gotten independently … you probably do have some obligation to say who is circulating that.”

Says Time’s Perry Bacon, Jr., “You tell readers as much as you can. You don’t need to burden your story with dutiful listings of where you got each bit of information first — if it’s something that’s publicly out there, and you checked it yourself. If it’s something harder to find, like a tape, maybe that’s a different decision.” The Times’s Nagourney, who did not write the aforementioned “tape” story but believes it was “perfectly appropriate material” to include in a piece, says he has decided not to use opposition research tips when he and the source could not agree on attribution.

Adam Clymer, a former political reporter and editor for the New York Times and now the political director of the National Annenberg Election Survey, says: “My attitude as an editor and reporter was if the negative material involves opinion, put it on the record.” But if it’s presented as fact, Clymer says, it doesn’t matter where the opposition research comes from; what matters is “is it true and is it relevant?”

If history is any guide, reporters say, both sides will continue to ramp up their oppo efforts as the election nears — and things are more likely than not to get down and dirty. “Maybe I don’t get the little envelopes with photos under the table,” says the Los Angeles Times’ Brownstein. “In that sense of opposition research, maybe people are stockpiling dirt on the other and waiting for much later in the year to put it out.” Noting that it is still early in the election season, Edwin Chen predicts that oppo will extend beyond “votes and quotes” in due time. “Some things never change,” he says.

What remains to be seen when the mud starts flying is which journalists will take the dirt and run (with) it, and which will pause to independently verify it or shoot it down — and which will choose to hold their noses and look the other way.

Liz Cox Barrett is a writer at CJR.