Americans for Prosperity has worked closely with the Tea Party since the movement’s inception. In the weeks before the first Tax Day protests, in April, 2009, Americans for Prosperity hosted a Web site offering supporters “Tea Party Talking Points.” The Arizona branch urged people to send tea bags to Obama; the Missouri branch urged members to sign up for “Taxpayer Tea Party Registration” and provided directions to nine protests. The group continues to stoke the rebellion. The North Carolina branch recently launched a “Tea Party Finder” Web site, advertised as “a hub for all the Tea Parties in North Carolina.”

The anti-government fervor infusing the 2010 elections represents a political triumph for the Kochs. By giving money to “educate,” fund, and organize Tea Party protesters, they have helped turn their private agenda into a mass movement. Bruce Bartlett, a conservative economist and a historian, who once worked at the National Center for Policy Analysis, a Dallas-based think tank that the Kochs fund, said, “The problem with the whole libertarian movement is that it’s been all chiefs and no Indians. There haven’t been any actual people, like voters, who give a crap about it. So the problem for the Kochs has been trying to create a movement.” With the emergence of the Tea Party, he said, “everyone suddenly sees that for the first time there are Indians out there—people who can provide real ideological power.” The Kochs, he said, are “trying to shape and control and channel the populist uprising into their own policies.”

Ideas don’t happen on their own,” Matt Kibbe, the president of FreedomWorks, a Tea Party advocacy group, told me. “Throughout history, ideas need patrons.” The Koch brothers, after helping to create Cato and Mercatus, concluded that think tanks alone were not enough to effect change. They needed a mechanism to deliver those ideas to the street, and to attract the public’s support. In 1984, David Koch and Richard Fink created yet another organization, and Kibbe joined them. The group, Citizens for a Sound Economy, seemed like a grassroots movement, but according to the Center for Public Integrity it was sponsored principally by the Kochs, who provided $7.9 million between 1986 and 1993. Its mission, Kibbe said, “was to take these heavy ideas and translate them for mass America. . . . We read the same literature Obama did about nonviolent revolutions—Saul Alinsky, Gandhi, Martin Luther King. We studied the idea of the Boston Tea Party as an example of nonviolent social change. We learned we needed boots on the ground to sell ideas, not candidates.” Within a few years, the group had mobilized fifty paid field workers, in twenty-six states, to rally voters behind the Kochs’ agenda. David and Charles, according to one participant, were “very controlling, very top down. You can’t build an organization with them. They run it.”

Around this time, the brothers faced a political crisis. In 1989, the Senate Select Committee on Indian Affairs investigated their business and released a scathing report accusing Koch Oil of “a widespread and sophisticated scheme to steal crude oil from Indians and others through fraudulent mismeasuring.” The Kochs admitted that they had improperly taken thirty-one million dollars’ worth of crude oil, but said that it had been accidental. Charles Koch told committee investigators that oil measurement is “a very uncertain art.”

To defend its reputation, Koch Industries hired Robert Strauss, then a premier Washington lobbyist; the company soon opened an office in the city. A grand jury was convened to investigate the allegations, but it eventually disbanded, without issuing criminal charges. According to the Senate report, after the committee hearings Koch operatives delved into the personal lives of committee staffers, even questioning an ex-wife. Senate investigators were upset by the Kochs’ tactics. Kenneth Ballen, the counsel to the Senate committee, said, “These people have amassed such unaccountable power!”

By 1993, when Bill Clinton became President, Citizens for a Sound Economy had become a prototype for the kind of corporate-backed opposition campaigns that have proliferated during the Obama era. The group waged a successful assault on Clinton’s proposed B.T.U. tax on energy, for instance, running advertisements, staging media events, and targeting opponents. And it mobilized anti-tax rallies outside the Capitol—rallies that NPR described as “designed to strike fear into the hearts of wavering Democrats.” Dan Glickman, a former Democratic congressman from Wichita, who supported the B.T.U. tax, recalled, “I’d been in Congress eighteen years. The Kochs actually engaged against me and funded my opponent. They used a lot of resources and effort—their employees, too.” Glickman suffered a surprise defeat. “I can’t prove it, but I think I was probably their victim,” he said.

The Kochs continued to disperse their money, creating slippery organizations with generic-sounding names, and this made it difficult to ascertain the extent of their influence in Washington. In 1990, Citizens for a Sound Economy created a spinoff group, Citizens for the Environment, which called acid rain and other environmental problems “myths.” When the Pittsburgh Post-Gazette investigated the matter, it discovered that the spinoff group had “no citizen membership of its own.”

In 1999, a jury found Koch Industries guilty of negligence and malice in the deaths of two Texas teen-agers in an explosion that resulted from a leaky underground butane pipeline. (In 2001, the company paid an undisclosed settlement.) And in the final months of the Clinton Presidency the Justice Department levelled a ninety-seven-count indictment against the company, for covering up the discharge of ninety-one tons of benzene, a carcinogen, from its refinery in Corpus Christi, Texas. The company was liable for three hundred and fifty million dollars in fines, and four Koch employees faced up to thirty-five years in prison. The Koch Petroleum Group eventually pleaded guilty to one criminal charge of covering up environmental violations, including the falsification of documents, and paid a twenty-million-dollar fine. David Uhlmann, a career prosecutor who, at the time, headed the environmental-crimes section at the Justice Department, described the suit as “one of the most significant cases ever brought under the Clean Air Act.” He added, “Environmental crimes are almost always motivated by economics and arrogance, and in the Koch case there was a healthy dose of both.”

During the 2000 election campaign, Koch Industries spent some nine hundred thousand dollars to support the candidacies of George W. Bush and other Republicans. During the Bush years, Koch Industries and other fossil-fuel companies enjoyed remarkable prosperity. The 2005 energy bill, which Hillary Clinton dubbed the Dick Cheney Lobbyist Energy Bill, offered enormous subsidies and tax breaks for energy companies. The Kochs have cast themselves as deficit hawks, but, according to a study by Media Matters, their companies have benefitted from nearly a hundred million dollars in government contracts since 2000.

That year, internal rivalries at Citizens for a Sound Economy caused the organization to split apart. David Koch and Fink started a new group, Americans for Prosperity, and they hired Tim Phillips to run it. Phillips was a political veteran who had worked with Ralph Reed, the evangelical leader and Republican activist, co-founding Century Strategies, a campaign-consulting company that became notorious for its ties to the disgraced lobbyist Jack Abramoff. Phillips’s online biography describes him as an expert in “grasstops” and “grassroots” political organizing. The Kochs’ choice of Phillips signalled an even greater toughness. The conservative operative Grover Norquist, who is known for praising “throat slitters” in politics, called Phillips “a grownup who can make things happen.”

Last year, Phillips told the Financial Times that Americans for Prosperity had only eight thousand registered members. Currently, its Web site claims that the group has “1.2 million activists.” Whatever its size, the Kochs’ political involvement has been intense; a former employee of the Cato Institute told me that Americans for Prosperity “was micromanaged by the Kochs.” And the brothers’ investment may well have paid off: Americans for Prosperity, in concert with the family’s other organizations, has been instrumental in disrupting the Obama Presidency.

In January, 2008, Charles Koch wrote in his company newsletter that America could be on the verge of “the greatest loss of liberty and prosperity since the 1930s.” That October, Americans for Prosperity held a conference of conservative operatives at a Marriott hotel outside Washington. Erick Erickson, the editor-in-chief of the conservative blog RedState.com, took the lectern, thanked David Koch, and vowed to “unite and fight . . . the armies of the left!” Soon after Obama assumed office, Americans for Prosperity launched “Porkulus” rallies against Obama’s stimulus-spending measures. Then the Mercatus Center released a report claiming that stimulus funds had been directed disproportionately toward Democratic districts; eventually, the author was forced to correct the report, but not before Rush Limbaugh, citing the paper, had labelled Obama’s program “a slush fund,” and Fox News and other conservative outlets had echoed the sentiment. (Phil Kerpen, the vice-president for policy at Americans for Prosperity, is a contributor to the Fox News Web site. Another officer at Americans for Prosperity, Walter Williams, often guest-hosts for Limbaugh.)

Americans for Prosperity also created an offshoot, Patients United Now, which organized what Phillips has estimated to be more than three hundred rallies against health-care reform. At one rally, an effigy of a Democratic congressman was hung; at another, protesters unfurled a banner depicting corpses from Dachau. The group also helped organize the “Kill the Bill” protests outside the Capitol, in March, where Democratic supporters of health-care reform alleged that they were spat on and cursed at. Phillips was a featured speaker.

Americans for Prosperity has held at least eighty events targeting cap-and-trade legislation, which is aimed at making industries pay for the air pollution that they create. Speakers for the group claimed, with exaggeration, that even back-yard barbecues and kitchen stoves would be taxed. The group was also involved in the attacks on Obama’s “green jobs” czar, Van Jones, and waged a crusade against international climate talks. Casting his group as a champion of ordinary workers who would be hurt by environmentalists, Phillips went to Copenhagen last year and staged a protest outside the United Nations conference on climate change, declaring, “We’re a grassroots organization. . . . I think it’s unfortunate when wealthy children of wealthy families . . . want to send unemployment rates in the United States up to twenty per cent.”

Koch began giving spectacularly large donations to the arts and sciences. And he became a patron of cancer research, focussing on prostate cancer. In addition to his gifts to Sloan-Kettering, he gave fifteen million dollars to New York-Presbyterian Hospital, a hundred and twenty-five million to M.I.T. for cancer research, twenty million to Johns Hopkins University, and twenty-five million to the M. D. Anderson Cancer Center, in Houston. In response to his generosity, Sloan-Kettering gave Koch its Excellence in Corporate Leadership Award. In 2004, President Bush named him to the National Cancer Advisory Board, which guides the National Cancer Institute.

Koch’s corporate and political roles, however, may pose conflicts of interest. For example, at the same time that David Koch has been casting himself as a champion in the fight against cancer, Koch Industries has been lobbying to prevent the E.P.A. from classifying formaldehyde, which the company produces in great quantities, as a “known carcinogen” in humans.

Scientists have long known that formaldehyde causes cancer in rats, and several major scientific studies have concluded that formaldehyde causes cancer in human beings—including one published last year by the National Cancer Institute, on whose advisory board Koch sits. The study tracked twenty-five thousand patients for an average of forty years; subjects exposed to higher amounts of formaldehyde had significantly higher rates of leukemia. These results helped lead an expert panel within the National Institutes of Health to conclude that formaldehyde should be categorized as a known carcinogen, and be strictly controlled by the government. Corporations have resisted regulations on formaldehyde for decades, however, and Koch Industries has been a large funder of members of Congress who have stymied the E.P.A., requiring it to defer new regulations until more studies are completed.

Koch Industries became a major producer of the chemical in 2005, after it bought Georgia-Pacific, the paper and wood-products company, for twenty-one billion dollars. Georgia-Pacific manufactures formaldehyde in its chemical division, and uses it to produce various wood products, such as plywood and laminates. Its annual production capacity for formaldehyde is 2.2 billion pounds. Last December, Traylor Champion, Georgia-Pacific’s vice-president of environmental affairs, sent a formal letter of protest to federal health authorities. He wrote that the company “strongly disagrees” with the N.I.H. panel’s conclusion that formaldehyde should be treated as a known human carcinogen. David Koch did not recuse himself from the National Cancer Advisory Board, or divest himself of company stock, while his company was directly lobbying the government to keep formaldehyde on the market. (A board spokesperson said that the issue of formaldehyde had not come up.)

James Huff, an associate director at the National Institute for Environmental Health Sciences, a division of the N.I.H., told me that it was “disgusting” for Koch to be serving on the National Cancer Advisory Board: “It’s just not good for public health. Vested interests should not be on the board.” He went on, “Those boards are very important. They’re very influential as to whether N.C.I. goes into formaldehyde or not. Billions of dollars are involved in formaldehyde.”

Harold Varmus, the director of the National Cancer Institute, knows David Koch from Memorial Sloan-Kettering, which he used to run. He said that, at Sloan-Kettering, “a lot of people who gave to us had large business interests. The one thing we wouldn’t tolerate in our board members is tobacco.” When told of Koch Industries’ stance on formaldehyde, Varmus said that he was “surprised.”