Last fall, Alex Gibney, a documentary filmmaker who won an Academy Award in 2008 for an exposé of torture at a U.S. military base in Afghanistan, completed a film called “Park Avenue: Money, Power and the American Dream.” It was scheduled to air on PBS on November 12th. The movie had been produced independently, in part with support from the Gates Foundation. “Park Avenue” is a pointed exploration of the growing economic inequality in America and a meditation on the often self-justifying mind-set of “the one per cent.” As a narrative device, Gibney focusses on one of the most expensive apartment buildings in Manhattan—740 Park Avenue—portraying it as an emblem of concentrated wealth and contrasting the lives of its inhabitants with those of poor people living at the other end of Park Avenue, in the Bronx.

Among the wealthiest residents of 740 Park is David Koch, the billionaire industrialist, who, with his brother Charles, owns Koch Industries, a huge energy-and-chemical conglomerate. The Koch brothers are known for their strongly conservative politics and for their efforts to finance a network of advocacy groups whose goal is to move the country to the right. David Koch is a major philanthropist, contributing to cultural and medical institutions that include Lincoln Center and New York-Presbyterian Hospital. In the nineteen-eighties, he began expanding his charitable contributions to the media, donating twenty-three million dollars to public television over the years. In 1997, he began serving as a trustee of Boston’s public-broadcasting operation, WGBH, and in 2006 he joined the board of New York’s public-television outlet, WNET. Recent news reports have suggested that the Koch brothers are considering buying eight daily newspapers owned by the Tribune Company, one of the country’s largest media empires, raising concerns that its publications—which include the Chicago Tribune and the Los Angeles Times—might slant news coverage to serve the interests of their new owners, either through executive mandates or through self-censorship. Clarence Page, a liberal Tribune columnist, recently said that the Kochs appeared intent on using a media company “as a vehicle for their political voice.”

“Park Avenue” includes a multifaceted portrait of the Koch brothers, telling the history of their family company and chronicling their many donations to universities and think tanks. It features comments from allies like Tim Phillips, the president of the Kochs’ main advocacy group, Americans for Prosperity, and from activists in the Tea Party, including Representative Michele Bachmann, of Minnesota, who share the Kochs’ opposition to high taxes and regulation. (It also contains a few quotes from me; in 2010, I wrote an article about the Kochs for this magazine, noting that they were funding much of the opposition to President Barack Obama by quietly subsidizing an array of advocacy groups.)

A large part of the film, however, subjects the Kochs to tough scrutiny. “Nobody’s money talks louder than David Koch’s,” the narrator, Gibney, says, describing him as a “right-wing oil tycoon” whose company had to pay what was then “the largest civil penalty in the E.P.A.’s history” for its role in more than thirty oil spills in 2000. At one point, a former doorman—his face shrouded in shadow, to preserve his anonymity—says that when he “started at 740” his assumption was that “come around to Christmastime I’m going to get a thousand from each resident. You know, because they are multibillionaires. But it’s not that way.” He continues, “These guys are businessmen. They know what the going rate is—they’re not going to give you anything more than that. The cheapest person over all was David Koch. We would load up his trucks—two vans, usually—every weekend, for the Hamptons … multiple guys, in and out, in and out, heavy bags. We would never get a tip from Mr. Koch. We would never get a smile from Mr. Koch. Fifty-dollar check for Christmas, too—yeah, I mean, a check! At least you could give us cash.”

For decades, federal funding for public broadcasting has been dwindling, and the government’s contribution now makes up only twelve per cent of PBS’s funds. Affiliates such as WNET are almost entirely dependent on gifts, some of which are sizable: in 2010, WNET received fifteen million dollars from James Tisch, the C.E.O. of Loews Corporation, and his wife, Merryl. (James Tisch is now the chairman of WNET’s board.) In New York City, such benefactors inevitably live in lavish buildings. Indeed, several relatives of WNET board members live at 740 Park.

In a recent phone interview, Neal Shapiro, the president of WNET, said that he grew concerned about the film, which he had not yet watched, after Ira Stoll, a conservative writer, lambasted it in the Post. On the Friday before the film’s Monday airdate, Stoll, whose Web site, Future of Capitalism, has frequently defended the Kochs, wrote, “If the station has any sense, it will use the time until then to reconsider its decision to air the program.” He added, “If it doesn’t, its trustees and donors, some of whom live on Park Avenue, may want to consider whether they want to continue supporting an institution that insults them so viciously.” The reviewer for the Times was more positive, writing, “There is plenty here to turn you into a Wall Street occupier,” and observing, “If you were still on the fence about whether to despise the superrich, this film will almost surely make a hater out of you.”

That Friday, Shapiro initially said, he called Koch at his office and told him that the Gibney film “was going to be controversial,” noting, “You’re going to be a big part of this thing.” Shapiro offered to show him the trailer, and added that he hoped to arrange “some sort of on-air roundtable discussion of it, to provide other points of view.” It could air immediately after the documentary. (Shapiro told me, “We did this after Ken Burns’s film on baseball, too. We like to have a local angle.”) Shapiro asked Koch, “Do you want to be involved?” He also offered Koch the opportunity to provide a written response, which the station could air after the show.

According to Shapiro, Koch, who rarely speaks in public, passed on the roundtable offer, saying, “I may just want to take it in and watch it, and form an opinion.” He agreed to think about contributing a written response.

Shapiro acknowledges that his call to Koch was unusual. Although many prominent New Yorkers are portrayed in “Park Avenue,” he said that he “only just called David Koch. He’s on our board. He’s the biggest main character. No one else, just David Koch. Because he’s a trustee. It’s a courtesy.” Shapiro, who joined WNET six years ago, from NBC News, added, “I can’t remember doing anything like this—I can’t remember another documentary centered around New York and key people in the city, and such controversial topics.”

PBS has standards for “editorial integrity,” and its guidelines state that “member stations are responsible for shielding the creative and editorial processes from political pressure or improper influence from funders or other sources.” A PBS spokesperson, when asked if it considered WNET’s actions appropriate, said, “WNET is in the best position to respond to this query,” noting that member stations are autonomous.

Every so often, it becomes known that a news outlet has altered its coverage in order not to offend a sponsor. In 1998, ABC News, which is owned by Disney, cancelled a report on the hiring of convicted pedophiles at Disney World. Days earlier, Michael Eisner, Disney’s chairman at the time, had told NPR, “I would prefer ABC not to cover Disney.” In Brill’s Content, a report on the incident said that it validated “the viewing public’s worst fears about conglomerate ownership of major news outlets.”

PBS has long been a political target of conservatives. During the last Presidential campaign, when Mitt Romney recommended eliminating government funding for public broadcasting, he echoed critics such as Newt Gingrich, who, in 1995, called public television élitist—a “little sandbox for the rich.” Conservatives have said that the WNET host Bill Moyers exhibits a “very strident left-wing bias,” and have suggested that characters on “Sesame Street” and “Arthur” indoctrinate children with left-wing values, such as acceptance of homosexuality. When Koch joined the boards of WGBH and WNET, it seemed to mark an ideological inroad, enabling him to exert influence over a network with a prominent news operation. Meanwhile, the member stations, by having Koch as a trustee, were inoculating themselves against charges of liberal bias, and positioning themselves to receive substantial new donations.

In fact, according to a well-informed source, WNET was about to embark on an ambitious capital campaign, and before Gibney’s film aired Koch had been planning to make a very large gift. “It was going to be a seven-figure donation—maybe more,” the source said. Shapiro denies that Koch’s patronage was a motive for his phone call.

Several days after our interview, Shapiro e-mailed me to say, “I now think my timeline was off… . I apparently misspoke.” He said that he had not called David Koch until the Monday that the Gibney documentary was to air. Shapiro added that he repeated his invitation to Koch to join the roundtable on Monday afternoon. Shapiro’s timetable is puzzling, given that WNET taped the roundtable that Monday at 11 A.M. The other participants had been invited the preceding Friday. Gibney, unlike Koch, was not asked to join the roundtable, which featured Jeff Madrick, a liberal fellow at the Roosevelt Institute, and Diana Furchtgott-Roth, a conservative fellow at the Manhattan Institute; they discussed income inequality in broad terms. The moderator, who noted that Koch was a trustee, repeatedly mentioned that Koch’s philanthropic contributions totalled a billion dollars.

Shortly before “Park Avenue” aired, Melissa Cohlmia, the chief spokesperson for Koch Industries, sent WNET a two-paragraph statement criticizing the film as “disappointing and divisive.” Cohlmia acknowledges, however, that neither she nor Koch had watched it. WNET aired the statement, unedited, immediately after the film. Cohlmia said that she based the critique on the trailer.

The weekend before “Park Avenue” aired, Gibney said, it was clear that “something weird had happened.” Shapiro called him at home. “He was very upset,” Gibney said. “They were thinking of pulling the program.” Gibney was told that the most pressing problem was Charles Schumer, the Democratic senator from New York. Schumer’s staff had called WNET, arguing that “Park Avenue” falsely accused the Senator of supporting tax loopholes for hedge-fund managers. Gibney double-checked his research and stood by his interpretation. Nevertheless, Shapiro told him that he planned to allow Schumer to add a response after the broadcast. But, Gibney noted, “Shapiro told me nothing about the Kochs.”

Gibney gives credit to Shapiro and WNET for airing his film uncensored. He is disappointed, though, that the station gave Koch and Schumer the last word. “They tried to undercut the credibility of the film, and I had no opportunity to defend it,” he said. Moreover, WNET replaced the introduction to “Park Avenue,” which was delivered by the actor Stanley Tucci, with one calling the film “controversial” and “provocative.” Gibney noted that he had asked to interview the Kochs while making “Park Avenue,” but they had refused. Cohlmia initially denied this, but after Gibney’s office provided me with the relevant e-mails she acknowledged that she had been contacted.

Shapiro emphasized that, by showing the Gibney film, he had made “the right call.” Still, spokespeople at WNET and PBS conceded that the decision to run the rebuttals was unprecedented. Indeed, it was like appending Letters to the Editor to a front-page article. Gibney asked me, “Why is WNET offering Mr. Koch special favors? And why did the station allow Koch to offer a critique of a film he hadn’t even seen? Money. Money talks.” He added that the Kochs’ willingness to issue a disclaimer without seeing the film “does not give me much confidence about how they might run the Tribune’s newspapers.”

Despite WNET’s hasty effort to mollify David Koch, “Park Avenue” apparently so offended him that he cancelled his plan to make a large donation. Cohlmia refused to confirm or deny this, as did Shapiro. “We do not discuss the details of gifts made by our donors,” he said, adding that he and Koch didn’t discuss the film after it aired.

Shapiro said that, in the end, he was comfortable with the journalistic standards of “Park Avenue,” and noted that he’d heard many positive comments from viewers, as well as negative ones. (The broadcast received high ratings for a PBS documentary.) But he said he felt blindsided by the Independent Television Service—the small arm of public television that funds and distributes independent films—for not giving him sufficient advance warning of the documentary’s contents. ITVS, which is based in San Francisco and was founded some twenty years ago by independent filmmakers, prides itself on its resistance to outside pressure. Its mandate is to showcase opinionated filmmakers who “take creative risks, advance issues and represent points of view not usually seen on public or commercial television.” “Park Avenue” was part of its popular series “Independent Lens,” which is aired by dozens of PBS member stations.

Shapiro acknowledged that, in his conversations with ITVS officials about “Park Avenue,” he was so livid that he threatened not to carry its films in the future. The New York metropolitan area is the largest audience for public television, so the threat posed a potentially mortal blow to ITVS. Several months earlier, it had succeeded in holding on to a prominent slot on WNET only after a public lobbying campaign by independent filmmakers.

Five days after “Park Avenue” aired, a producer at Gibney’s firm, Jigsaw Productions, was shopping in a clothing store in SoHo at the same time as two other customers: Thomas and Alice Tisch, who live at 740 Park. They are the brother and sister-in-law of James Tisch. The producer recalls that, after the Tisches heard her mention to another customer where she worked, they denounced what they called the film’s incendiary rhetoric against the rich. They went on for twenty minutes, warning that such hateful attitudes could lead many wealthy New Yorkers to move to Florida, where the taxes are lower, and arguing that neighbors of theirs who spent millions of dollars on parties helped waiters and caterers.

There were reverberations on the West Coast, too, at the headquarters of ITVS. “Neal Shapiro was on a rampage against ITVS,” a public-television executive said. In an effort to placate him, ITVS sent him a box of candy. “It was delicious,” Shapiro told me.

A week later, Tia Lessin and Carl Deal, respected documentary filmmakers who were working on a project with ITVS, shared some good news with their funders: their film, which was about the influence of money on American politics after the Supreme Court’s 2010 decision in the Citizens United case, had been accepted by the Sundance Film Festival and would compete for Best Documentary.

Lessin and Deal had provisionally called the film “Citizen Corp,” but they worried that the title made it sound like a film about a corpse. After Sundance officials pressed for a final title so that they could start promoting it, Lessin and Deal told ITVS that they had settled on “Citizen Koch.”

The new title reflected the evolution of the narrative: reporting had focussed increasingly on the pitched battle in Wisconsin over the efforts of Scott Walker, the Republican governor, to ban collective bargaining by public-sector-employee unions. As the Times reported, Koch Industries was among Walker’s primary financial backers in his 2010 gubernatorial campaign.

Lessin and Deal had received widespread acclaim for their 2008 film about Hurricane Katrina, “Trouble the Water,” which won the Sundance Film Festival’s Grand Jury award. They had been nominated for an Academy Award and had been producers on two films made by the progressive activist Michael Moore, “Fahrenheit 9/11” and “Bowling for Columbine”; Lessin had worked with Martin Scorsese on documentaries about Bob Dylan and George Harrison.

Lessin and Deal say that they are registered with neither political party, but an early synopsis of their proposed film reflected the liberal view that the Citizens United ruling had endangered democracy by drowning out ordinary voters’ concerns in a surge of corporate cash. This stance is scarcely novel, but their narrative focus was original: working-class Republicans who felt betrayed by the Party’s attack on public-employee unions in Wisconsin. Virtually from the start, the Kochs had figured prominently in their proposal. On February 12, 2012, Lessin and Deal sent ITVS a six-minute preview that mentioned the Kochs multiple times as major contributors to conservative candidates and causes. At one point, the words “TWO BILLIONAIRE EXTREMISTS” appeared onscreen.

Lessin and Deal kept meticulous records of their exchanges with ITVS officials, and it seems that the collaboration was relatively smooth until Gibney’s documentary aired. In April, 2012, ITVS recommended that the film receive a hundred and fifty thousand dollars in funding. “Please accept this as confirmation and congratulations,” the ITVS notification said. It went on, “Everyone here at ITVS looks forward to working with you on your very exciting and promising program.” A few weeks later, ITVS sent a multipage contract to the filmmakers, and negotiations seemed close to a resolution just before “Park Avenue” aired. Arash Hoda, the production manager at ITVS, sent Lessin and Deal an upbeat e-mail about the contract, saying, “This looks good … moving forward.”

Claire Aguilar, then the vice-president of programming at ITVS, was similarly encouraging after watching a two-and-a-half-hour rough cut bearing the title “Citizen Koch.” She sent the filmmakers an e-mail that said, “Great rough cut—thank you for sharing it.” She said that she wasn’t crazy about the new title, but she wasn’t adamantly opposed to it, either.

A television producer knowledgeable about ITVS said that “there had been no concern” until the Gibney documentary aired, and that few executives there had watched the rough cut. Suddenly, many ITVS officials seemed desperate to see it. Lessin and Deal were told to send a password-protected video link of the unfinished film to ITVS. Within days, the video had been played almost thirty times. “It was a real problem, because of ‘Park Avenue,’ ” a public-television official aware of the situation said. “Because of the whole thing with the Koch brothers, ITVS knew WNET would never air it. Never.”

According to the television producer, it seemed like ITVS executives “didn’t want it to get to higher levels at PBS” that another Koch film was in the pipeline: “They were trying to hide things. They didn’t want ITVS’s name connected to it at Sundance. They were afraid of two things—that PBS would catch wind of it, and that Lessin and Deal would go to the press and say that PBS didn’t want them talking about David Koch.”

Lessin and Deal took notes on their phone conversations with ITVS officials, which show that they were pushed to drop the Koch name from the title and to place less emphasis on the brothers’ political influence. On December 7th, the filmmakers’ notes indicate, Lois Vossen, the vice-president and senior series producer at ITVS, warned Lessin and Deal that the title “Citizen Koch” was “extraordinarily problematic.” Vossen’s job is to select films for “Independent Lens” and then pitch the programs to PBS. She told Lessin and Deal that the new title would make it exceedingly hard for her to champion the film at PBS, saying, “I would say I feel as though I would have both hands tied behind my back, and probably duct tape over my mouth.” (Vossen, reached for comment, said that she was just getting off a plane and would try to call back. She never did.)

The messages from ITVS officials grew confusing. Aguilar again praised the film as “great,” and said, “I think you’ve preserved the anger of the film, which I love.” Other officials, though, kept urging the filmmakers to change the title, add negative material about Democrats, and delete an opening sequence that showed Sarah Palin speaking at a rally sponsored by Americans for Prosperity, the Kochs’ main advocacy group. Several times, Lessin and Deal asked ITVS officials if Koch’s trusteeship at WNET was a factor. During the phone meeting on December 7th, Vossen said, “I can absolutely assure you that ITVS does not want your film to be buried.” She said of the title, “I think you understand why it’s problematic… . We live in a world where we have to be aware that people with power have power.”

During a conference call on January 14th, Jim Sommers, the senior vice-president of content for ITVS, acknowledged to Lessin and Deal that, after Gibney’s film aired, there was “one station that gave us a lot of push-back about it.” Was the station in New York? He said, “Ha, ha, ha, that might be it.” According to the television producer, “They kept using words like ‘balance,’ but what they really meant was ‘Get rid of the Koch story line.’ “

Lessin said of ITVS staffers, “These are good people. Our sense was that there was something bigger than them going on. They weren’t being straight with us.” Deal said, “They’re not supposed to be spineless bureaucrats. ITVS was set up by filmmakers to have a voice in the public-broadcasting universe. Their mission statement basically says, ‘Be brave, be independent.’ We never thought they’d back down.”

Ruby Lerner, the president and the executive director of Creative Capital, which helped fund Lessin and Deal’s Katrina film, said that she regards the “self-censorship” practiced by public-television officials to be “a scarier thing” than the overt kind: “They seem to be putting themselves in the Koch brothers’ shoes and trying not to offend them.” Even on public television, she argued, patronage buys influence. “It raises issues about what public television means,” she said. “They are in the middle of so much funding pressure.”

Michael Moore remembers Lessin and Deal fondly: Lessin got arrested while working with him on a documentary about labor issues at Disney World, and Deal found file footage of Paul Wolfowitz getting his hair slicked down by an aide, after Wolfowitz helpfully spat on his own comb. (The bit appeared in “Fahrenheit 9/11.”) Moore said that he’s not surprised that the two ran into obstacles in public television, given Koch’s trustee role, adding, “The words ‘chilling effect’ came immediately to mind.”

In January, the film débuted at Sundance, where it was respectfully reviewed. A critic at Variety argued that “Citizen Koch,” still in unfinished form, had too many plot strands, but concluded that it “vividly displayed” the “warping effect” of the Citizens United decision.

Lessin and Deal began to suspect that ITVS was dragging out negotiations. But they kept editing the film, following notes that ITVS had given them. Deal said, “Although we made many changes, they never looked at the new cut. They just kind of stopped.” On April 15th, ITVS notified Lessin and Deal that it had “decided not to move forward with the project.” Lessin said, “We were in shock. We had a deal.”

ITVS officials ascribe their decision to growing editorial differences. They issued a prepared statement: “ITVS commenced negotiations to fund the film ‘Citizen Corp’ based on a written proposal. Early cuts of the film did not reflect the proposal, however, and ITVS ceased negotiations.”

Lessin and Deal said that this is untrue. Although they had changed the title, they said, in a joint statement, “The film we made is identical in premise and execution to the written and video proposals that ITVS green-lit last spring. ITVS backed out of the partnership because they came to fear the reaction our film would provoke. David Koch, whose political activities are featured in the film, happens to be a public-television funder and a trustee of both WNET and WGBH. This wasn’t a failed negotiation or a divergence of visions; it was censorship, pure and simple.” The filmmakers consider this an ironic turn: “It’s the very thing our film is about—public servants bowing to pressures, direct or indirect, from high-dollar donors.”

In the end, the various attempts to assuage David Koch were apparently insufficient. On Thursday, May 16th, WNET’s board of directors quietly accepted his resignation. It was the result, an insider said, of his unwillingness to back a media organization that had so unsparingly covered its sponsor.