The stakes in the political battle over climate-change "denial" may get higher.
The American Legislative Exchange Council, the right-leaning partnership of state lawmakers and corporations, is threatening defamation lawsuits against activists who say or suggest the group denies global warming.
Such lawsuits would face extraordinarily long odds, but the fight over the "denier" label that environmental and liberal groups commonly lob at conservative and fossil-fuel backed interests and politicians has become front-and-center in the climate debate.
ALEC's lawyers last month sent newly revealed "cease and desist" letters to the advocacy groups Common Cause and the League of Conservation Voters objecting to their public characterizations of the group. The letters demand an end to "inaccurate" statements and removal of "false and misleading material" from the advocacy groups' websites, warning that if "defamatory statements" continue, ALEC will weigh "any and all necessary legal action."
It would be difficult for ALEC, a group that engages in public debate, to convince a court that its adversaries' speech about its climate views and policies constitutes defamation, legal experts say.
"I doubt very much that it could be litigated as defamation, libel, or slander," said John F. Banzhaf III, a law professor at George Washington University.
Georgetown University law professor Rebecca Tushnet said it's "difficult to imagine any possible circumstance under which this could be defamatory." She noted that the bar for showing defamation is that the action is knowing or reckless, false, and causes "reputational harm."
"Indeed, it's hard to imagine how ALEC could show any one of those three, much less all, given the antiregulatory initiatives on which ALEC's reputation is built," Tushnet said.
ALEC did not respond to a request for comment.
But even long-shot lawsuits would open the door for the courts to get involved with the tricky question of what, exactly, constitutes "denial" of climate change, a debate already playing out in newsrooms and elsewhere.
The New York Times, in February, looked at the heated battles over labels for various viewpoints on climate. Scientists and science educators like Bill Nye "the science guy" have publicly urged the media to ditch the term "skeptic" in favor of "denier" to describe people who dispute the scientific consensus that humans are the major driver of global warming.
If ALEC follows up with a lawsuit, it would move these years-old semantic and political battles over "denial" into the legal realm, and raise the stakes for groups by adding new legal costs.
It would not be the first defamation lawsuit related to climate change. In 2012, the prominent climate scientist Michael Mann sued National Review magazine and the Competitive Enterprise Institute (CEI) over their blog posts that alleged his research is fraudulent. CEI's post also compared Mann, a Pennsylvania State University professor, to convicted child molester Jerry Sandusky.
ALEC is pushing back against the "denier" tag at a sensitive time for the group, whose corporate members face pressure from climate activists. In recent months, a number of major corporations including Google, Facebook, and BP have abandoned the group.
Banzhaf said ALEC could try to use tort claims beyond defamation, such as "intentional interference" with contracts, noting that ALEC has been losing corporate members amid criticism of its climate stances. But he predicted that it wouldn't work. "I don't think, quite frankly, that any of them would be successful," Banzhaf said.
ALEC, for its part, accuses activists of mischaracterizing its views. "ALEC's position is clear. ALEC does not deny climate change," the group said in its early-March letter to Common Cause and a separate letter to LCV.
The group points to its standing position that "human activity has and will continue to alter the atmosphere" and "may lead to demonstrable changes in climate, including a warming of the planetary mean temperature." Those phrases are found in "model legislation" ALEC has developed that also says: "Such activity may lead to deleterious, neutral, or possibly beneficial climatic changes."
But Common Cause's response delves more deeply into what constitutes climate-change denial.
"The characterization of an individual or entity as one that denies climate change is well understood to refer not only to those who deny outright that earth's climate is changing, but more broadly to individuals or organizations who, while admitting that changes in the earth's atmosphere are occurring as a result of human activity, question or cast doubt on the scientific evidence regarding climate change or its impact," their letter states.
LCV and Common Cause, in separate letters from their attorneys back to ALEC last month, say they're not backing down from their criticisms. LCV notes that its comments about ALEC are "fully protected by the First Amendment."
ALEC's letter criticizes an LCV site that, among other things, accuses the group of "preparing to work with their climate science-denying allies in Congress and state houses" to thwart EPA policies.
Common Cause, 350.org, Greenpeace, and other groups have also launched a new website titled "ALEC and Climate Change Denial" to make their case.