A big problem with speaking income is that, whatever the use of the money—the mortgage, the kids’ college fund, better bottles of wine—the journalist is precisely aware of the source. Even in the case of speaking fees donated to charity, a US citizen is eligible for a tax break, and the appreciation and good works of the group on the receiving end of the donation are also, in a way, things of value to the giver.

And such fees surely have an impact on coverage, if not necessarily an obvious or insidious one. A financial journalist who has been paid for speeches by Wall Street firms told me that he would never write a story about any company that has paid him a fee. Great, except that the more speaking he does, the more he will be restricting his range of coverage. Unconscious self-censorship could be a factor, too, as journalists who enjoy Wall Street’s money might come to feel more simpatico toward their benefactors’ perspectives on various issues. It’s a pretty typical human reaction, after all. The New York Times reported recently that doctors who take money from drug makers often are more willing than doctors who don’t to prescribe drugs in “risky” ways. Why should journalists be any more immune to this than physicians are?

For journalists who take money from Wall Street firms but don’t cover financial issues, the conflict is less apparent. Who cares if a celebrity journalist gets paid to serve as marketing bait for a private-equity firm trolling for new investors? My objection is perhaps more aesthetic than ethical: It’s a little cheesy for a journalist to serve such slick, mercenary purposes. As for big-name journalists who help financial firms buff the brand, that work is better left to the likes of Sam Waterston, the celebrity pitchman for TD Ameritrade.

My focus here is on Wall Street because it is such a prominent source of speaking income, and because of its salience in today’s news. But the same questions and objections apply to the health-care sector, also a major source of funds, and any other industry the press covers. The damage is to reputation—to the fee-taking journalists and more broadly to journalism itself. “I hate the idea of these guys doing it,” a veteran financial journalist, who doesn’t give speeches for money, told me. “Everyone is wheeling and dealing in this culture. Even a perceived conflict of interest ruins it not only for the journalist, but for journalism. Reputation is everything.”

That’s harsh, but it seems telling that, with the notable exceptions of Gillian Tett, Michael Lewis, and Martin Wolf, most of the journalists I tried to talk to about their speaking appearances resisted comment, or would only talk anonymously—which is a little ironic. One prominent scribe pleaded not to be mentioned at all. (Sorry, no passes.) I still have the bite marks on my neck from a telephone conversation with another who demanded to know whether he was the target of a “hostile inquiry.”

The good news is that leading news organizations have in place strict policies to limit the practice of taking fees for speeches or even to ban it entirely, on the premise that the practice is inherently problematic.

At The Wall Street Journal, Robert Thomson, who was hired as managing editor in 2008, has set the gold standard, decreeing a flat ban on paid speeches. Staff under his watch can’t take fees for speeches from any source, profit or nonprofit—not even if they give the money to charity—and they can’t take payments for travel or other expenses. “If we think a speech is important for us to do, we do it on our dime, to avoid any possible conflict,” says Alan Murray, a deputy managing editor at the paper. Editorial-page staffers are permitted to take speaking fees from nonprofits but not from for-profits.

Paul Starobin , a former Moscow bureau chief of Business Week, is the author of After America: Narratives for the Next Global Age.