Commentary by Naomi Oreskes and Erik M. Conway for the Los Angeles Times: If some of the attacks on the credibility of climate science feel familiar, there's a reason.

If some of the attacks on the credibility of climate science feel familiar, there's a reason. With their unattributed claims downplaying the severity of the problem and their vague allegations of scientific impropriety, the assaults are the latest in a long tradition of organized efforts by industry and free-market enthusiasts to undermine the credibility of science they don't like.

One early campaign was launched by tobacco companies. Seeking to prevent government regulation of its product, the American cigarette industry created the Council for Tobacco Research to generate research disputing the work of mainstream scientists. "Doubt is our product," said a 1969 industry memo, "since it is the best means of competing with the 'body of fact' that exists in the minds of the general public." Fighting regulation meant creating doubt about the health effects of smoking. The strategy proved enormously successful, helping prevent most regulation of tobacco products until 2009, nearly six decades after the carcinogenic properties of tobacco were established.

The strategy was expanded beyond the cigarette industry in part because of the efforts of physicist Frederick Seitz, a former president of the National Academy of Sciences who went on to direct R.J. Reynolds' biomedical research program. In 1984, he joined forces with astrophysicist Robert Jastrow and nuclear physicist William Nierenberg to establish the George C. Marshall Institute. Their goal was to defend Ronald Reagan's Strategic Defense Initiative — better known as "Star Wars." For the rest of the decade, the institute defended SDI by exaggerating the Soviet threat and by attacking the credibility of SDI's opponents. One 1987 article by Jastrow was headlined "America has Five Years Left!" It warned that without action, Soviet superiority would soon lead to crushing defeat for the West.

After the collapse of the Soviet Union, the institute found a new enemy: environmentalists, who were viewed as "watermelons" — green on the outside, red on the inside. Nierenberg had paved the way for this target shift, working behind the scenes to weaken the conclusions of important government reports on acid rain and climate change in 1983 and 1984.

In the 1990s, Nierenberg, Jastrow and Seitz tried to blame the sun for global warming and volcanoes for the Antarctic ozone hole. They also launched personal attacks on scientists who had done important work on climate issues. In one egregious example, in 1995 they teamed with an industry group, the Global Climate Coalition, to accuse a young scientist, Benjamin Santer of "scientific cleansing" — removing uncertainty from the Intergovernmental Panel on Climate Change's Second Assessment Report. Santer had played a key role in demonstrating the role of human activity in global warming; by attacking him via the Wall Street Journal, they hoped to foster doubt about the IPCC and one of its key conclusions: that humans have caused global warming.

Meanwhile, the tobacco industry had begun to broaden its own pushback against tobacco regulation into a broad campaign against all science. Philip Morris worked with a public relations firm to create the Advancement of Sound Science Coalition. Headed by lobbyist Steven Milloy, TASSC tried to discredit as "junk science" research that industry didn't like. One product of this effort was "Bad Science: A Resource Book," whose sound-bite size "messages" included (apparently without irony): "Too often science is manipulated to fulfill a political agenda." Milloy's "junk science" website contained attacks on climate science, ozone depletion, acid rain and pesticide regulation.

Today the network of institutions attempting to undermine science (with funding from industry) is vast. The top tier of the network is a set of political think tanks dedicated to promoting free markets and advocating for limited government. They include the Cato Institute, the Heritage Foundation, the American Enterprise Institute, the Heartland Institute and the Competitive Enterprise Institute. In turn, they are linked to myriad smaller groups. The Competitive Enterprise Institute, for example, organized the Cooler Heads Coalition, which describes itself as "focused on dispelling the myths of global warming by exposing flawed economic, scientific and risk analysis."

Cold Warriors all, Jastrow, Nierenberg and Seitz saw their campaigns as part of a larger effort to defend freedom. In defense of tobacco, fellow physicist Fred Singer, who also worked to discredit the science of ozone depletion and acid rain, wrote, "If we do not carefully delineate the government's role in regulating (danger), there is essentially no limit to how much government can ultimately control our lives." The Cold War was a conflict between economic ideologies — what George Soros calls market fundamentalism versus communist state control. Market fundamentalists saw the growth of environmental regulation as a form of creeping government control.

As science found more and more evidence of the environmental and health effects of industrial activity, which suggested the need for regulation, market fundamentalists increasingly turned against that science. In the name of "freedom," the American public has been deliberately misinformed about important issues of human health and environmental protection. But it remains difficult to imagine how lies can set us free.

Naomi Oreskes is a professor of history and science studies at UC San Diego. Erik M. Conway is a historian of science living in Pasadena, Calif. They are the authors of "Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming." They wrote this for the Los Angeles Times.