Consider the case of Margaret Sanger, the path-breaking advocate of birth-control education, who in 1921 founded what would become Planned Parenthood. In her time, pamphlets on birth control were still subject to Victorian-era anti-obscenity laws. Sanger and her allies fought for the right to distribute them anyway, and won. But a court rejected the argument that the distribution of the pamphlets was a charity that qualified for tax exemption. Zunz writes: “They were unable to change Treasury’s position that the state could not subsidize challenges to existing law, regardless of the flaws of that law.

“No issue,” Zunz writes, “came closer to embodying all the difficulties inherent in attempts to define the proper nature of philanthropic causes and the limits on philanthropic action and its interaction with democratic politics.”

One reason this is relevant here is the importance of the independence of the press from government or private-interest interference.

“There were three estates in Parliament,” Edmund Burke is said to have exclaimed in 1787, “but, in the Reporters’ Gallery yonder there sat a fourth estate more important far than they all.”

Americans know in their bones that the independence of that fourth estate is to be guarded. We’ve seen how work in the public realm that is funded entirely or in part by government subsidy comes under intense scrutiny for perceived bias to the left or right. The culture war of the 1980s that embroiled the National Endowment for the Arts is an example. Or the battles over public broadcasting after the Corporation for Public Broadcasting, created by an act of Congress in the Johnson administration, got into the act. Things only got worse as public broadcasters like PBS and NPR aired reports and documentaries on civil rights, the Vietnam War, and the general cultural revolution taking place in the latter half of the twentieth century.

Then there is the pressure of private money. Zunz provides reminders of the history of philanthropy in advancing particular causes. In 1945, he notes, Pennsylvania oilman J. Howard Pew, who had been looking for a way to counter what he considered philanthropy’s broad, irreligious, and even communist views, threw charitable support behind Guideposts, the magazine of Norman Vincent Peale, pastor of the Fifth Avenue Marble Collegiate Church. “All we need to do is state our case,” Peale told Pew, and “keep driving it home. It will win its own way, I am sure, because it is the truth.” Pew avidly supported McCarthyism, as well as Tennessee Congressman B. Carroll Reece’s 1953 investigations into whether large philanthropic organizations were supporting “efforts to overthrow our government and to undermine our American way of life.”

Philanthropists give money to advance causes. The press is not the same sort of cause as poverty or malnutrition, or education or aid to immigrants. It is, after all, the medium through which information about precisely the issues philanthropy has traditionally addressed is broadcast to the public.

Of course, the press has always had owners—wealthy families or big corporations—that have pushed the journalism in certain directions. Whether news outlets can guarantee their independence any better with a large for-profit corporate owner than with major nonprofit funders remains to be seen. But one recent and controversial report found that nonprofit news organizations already have a mixed record when it comes to being objective and transparent about the sources of their support.

Published in July 2011 by the Pew Project for Excellence in Journalism, the study found:

The 46 national and state-level news sites examined—a group that included seven new commercial sites with similar missions—offered a wide range of styles and approaches, but roughly half, the study found, produced news coverage that was clearly ideological in nature.

In general, the more ideological sites tended to be funded mostly or entirely by one parent organization—though that parent group may have various contributors.

On the other hand, the study found that sites that had a broad base of support—a larger number of smaller funders—were more likely to produce journalism as the traditional nonpartisan mission would have it:

Sites that offered a mixed or balanced political perspective, on the other hand, tended to have multiple funders, more revenue streams, more transparency and more content with a deeper bench of reporters. The six most transparent sites studied, for instance, were among the most balanced in the news they produced.

Or as media critic Jack Shafer put it in a column on Slate in September 2009, “No matter how good the nonprofit operation is, it always ends up sustaining itself with handouts, and handouts come with conditions.”

Tom McGeveran is a co-founder and editor of Capital New York, a for-profit news and commentary site that recently raised $1.7 million from private investors. He previously was editor of The New York Observer.