On the morning of October 11, 2016, in what today might seem a different political era, five middle-aged climate activists from Washington and Oregon posted a well-reasoned if somewhat unusual letter to President Barack Obama. In the letter the activists laid out the case, as supported by science that Obama claimed to accept, for an expeditious end to the extraction and burning of coal and tar-sands oil in order to have a shot at the Paris Agreement goal of limiting global warming to 1.5 degrees Celsius above the preindustrial average. Pointing to the lack of any plausible legal means to bring about such a halt, they went on to inform the president that their only available option was to engage in direct action: “which is why we are acting today,” they wrote, “to shut down the five pipelines used to transport tar sands oil from Alberta [Canada] into the US.”

With civilization and the future of human life itself in the balance, “the sane choice is to act now,” the activists wrote to Obama. “Which raises the practical question of what a concerned citizen should do when our governments and economic systems are committed to a course of global suicide and are willing and able to bend the political system and civic discourse to their will.”

The action that those five concerned citizens, now known to the world as the Valve Turners, took that day—manually closing the emergency shut-off valves on tar-sands pipelines in Washington, Montana, North Dakota, and Minnesota, then peacefully awaiting their arrest—surely stands among the boldest acts of nonviolent civil disobedience, on climate or any other issue, in memory. As Reuters reported, it “shook the North American energy industry,” stopping the flow of tar-sands oil from Canada, equaling some 15 percent of daily US consumption. They acted independently, without the backing of major environmental and climate groups. Three of the Valve Turners have been tried and convicted of felony charges—Ken Ward in Washington, Leonard Higgins in Montana, and Michael Foster in North Dakota—and one of them, Foster, has served time in prison.

Now, in conservative Clearwater County in northwest Minnesota, the remaining two Valve Turners, Annette Klapstein and Emily Johnston, along with support-team member Ben Joldersma, are set to go to trial in district court on October 8. In what is already a landmark case, District Court Judge Robert Tiffany issued a written opinion granting use of the “necessity defense” (denied in the other three cases), and in July the Minnesota Supreme Court allowed the rarely approved defense to go forward. That means Klapstein, Johnston, and Joldersma will testify before a jury—along with expert witnesses such as former top NASA climate scientist James Hansen (now of Columbia University), Middlebury environmental scholar and 350.org founder Bill McKibben, Princeton political scientist Martin Gilens, Harvard Law School’s Lawrence Lessig, and others—that their actions were necessary and legally justified in response to the threat of catastrophic climate change. If the judge instructs jurors to consider the evidence of necessity, it will be a historic first in a climate-related jury trial in the United States—at a time when states are cracking down on peaceful protest against fossil-fuel infrastructure.

“Valve Turners” Annette Klapstein, left, and Emily Johnston on the morning of October 11, 2016, in front of shutoff stations for Enbridge Line 4 and Line 67 pipelines near Leonard, Minnesota.(Steve Liptay)

Climate change is showing up in court quite a lot of late. Cities from San Francisco to Boulder to Baltimore—and even the state of Rhode Island—have sued Big Oil for climate damages. New York and Massachusetts are investigating whether Exxon-Mobil deceived the public about what it has known for decades about the threat of climate change. Most dramatic of all, 21 youth plaintiffs are suing the federal government for its failure, under public-trust doctrine and the US Constitution, to protect a livable climate. That case, Juliana v. United States, has survived multiple appeals to dismiss, and this summer the Supreme Court allowed it to proceed. The trial date is set for October 29 in federal court in Oregon.

Much like the youth plaintiffs’ case, the arguments underpinning the climate-necessity defense resonate powerfully in this political moment—and not only as a response to our climate emergency, but equally and inseparably, as a response to our political emergency, the crisis of our democracy, which long predates Donald Trump and is, in fact, among the root causes of the climate crisis itself. Far from being the inevitable result of “human nature” (as an entire issue of The New York Times Magazine was recently devoted to arguing, conveniently letting the fossil-fuel industry and its political accomplices, including liberal elites, off the hook), our current predicament is in large part the result of deception, obstruction, and the antidemocratic rigging of our political and economic system by corporations and private wealth. The climate-necessity defense addresses these root causes head-on, offering an indictment of a political system in which ordinary citizens have no viable option but to take direct action—and inspire others to do the same. As we’re about to see in Minnesota, the best defense may actually be a strong offense.

“This is the only way we get their attention, this is the only way we can put a stop to it, by putting our own bodies on the line. All other avenues have been exhausted at this point.” Annette Klapstein, a retired lawyer for the Puyallup tribe in Tacoma and a mother of two, is speaking to a camera held by documentary filmmaker Steve Liptay in the gray early-morning light on that day in October 2016. She sits in the passenger seat of a parked car near the entrance to the fenced-in shutoff valves for Enbridge Lines 4 and 67 outside Leonard, Minnesota. “So, for the sake of the children and the earth that we love, I’m ready to do this.” (Liptay, who has worked closely with filmmaker Josh Fox, produced a sleek, pulse-pounding video of the action and is at work on a feature-length documentary about the Valve Turners; for his journalistic efforts in Minnesota he received criminal charges, only recently dropped.)

Like their valve-turning comrades in Washington, Montana, and North Dakota at that hour, Klapstein and Johnston proceeded to use heavy-duty bolt cutters to enter the enclosures and break the chains fastening the shut-off valve wheels. Meanwhile, according to plan, Joldersma called officials at Enbridge, the pipeline company, to inform them of the situation, giving them the opportunity to shut down the pipelines remotely—which the company promptly did, before Johnston and Klapstein could finish the job.

“We cannot work through our political system, because its values are nothing but profit,” Klapstein told me recently. “We live in an oligarchy, not a democracy.” When asked what people like her, who may feel powerless, can do to be effective under such circumstances, she answered, “It’s very much in the interest of the capitalist political system to make us feel powerless, to make us feel that we can’t do anything.” And yet, she said, “ultimately, they cannot win if we do not consent. If we really withdraw our consent, if we really go out there and sit down in front of the machine, eventually they can no longer operate it. And at this point, that is our only option.”

It’s important to remember that the Valve Turners planned and carried out their action during the 2016 election campaign, and that when they turned the valves it was still a month before Election Day—when they assumed, like most other observers, that Hillary Clinton would be elected president. And they knew that Clinton, with her campaign’s ties to the oil and gas industry and her enthusiasm for fracking as secretary of state, had shown little interest in climate policy and was unlikely to be more ambitious than Obama—whose “all of the above” energy strategy yielded an oil-and-gas bonanza, canceling out whatever meager greenhouse emissions cuts his administration could claim, despite the brave talk around Paris, and only accelerated our catastrophic trajectory.

The Valve Turners have had the critical support of two small, young organizations that arose in this political context, during the Obama administration’s last years, with the purpose of directly confronting the dire scientific and political realities of our moment. The first of these outfits, the Climate Disobedience Center, supports people who are ready to take nonviolent direct action in ways commensurate with the climate catastrophe, and was co-founded in 2015 by Ken Ward and Jay O’Hara (whose lobster-boat blockade of a coal tanker and subsequent trial I wrote about for The Nation), climate activist Tim DeChristopher (who famously served 21 months in prison for monkeywrenching a 2008 federal auction of oil and gas drilling leases in Utah), and longtime climate movement organizer Marla Marcum. (Their stories, and how the Climate Disobedience Center came together, are central to my 2015 book.)

The other outfit, without which this trial might not be happening, is the Climate Defense Project, founded by recent Harvard Law School graduates Alice Cherry, Ted Hamilton, and Kelsey Skaggs, in order to support frontline activists. Veterans of the fossil-fuel divestment campaign (as students they sued Harvard in a groundbreaking divestment lawsuit), they share with the Climate Disobedience Center a sophisticated, systemic analysis of the climate crisis and its political roots, as well as an understanding of the historical role of social movements—and courts—in catalyzing deep societal shifts. The CDP’s Cherry and Skaggs are assisting a defense team in the Minnesota case that includes lead attorney Tim Phillips of Minneapolis and Lauren Regan of the Seattle-based Civil Liberties Defense Center.

“The necessity defense offers a powerful framing of why people do civil disobedience,” Skaggs told me in a recent interview. “It’s a powerful way of explaining to other people why they would take a risk like this—as reasonable human beings. I believe that’s what we need to change political consciousness.”

In other words, one might say, putting the question of climate necessity before a jury is an exercise in democracy—at a time when democracy itself is failing.

The climate-necessity defense has made significant strides in recent years. While peace and antinuclear protesters engaging in civil disobedience have successfully mounted necessity defenses since the 1970s, the first successful use in a climate case appears to have been in the 2008 Kingsnorth Six trial in the United Kingdom, in which Greenpeace activists were acquitted of charges stemming from a coal-plant protest. Until very recently, climate activists in this country have not been allowed by US courts to argue necessity. Tim DeChristopher attempted to use a necessity defense in his 2011 federal trial in Utah, but the judge in the case rejected it. Since then, a number of climate activists have tried to use the defense, with varying results. In 2014, the judge in Ward and O’Hara’s trial in Massachusetts cleared the way for them to use a necessity defense, but the district attorney dropped the charges on the morning of the trial and very publicly joined their cause—giving credibility to the necessity argument without having it aired in court.

The following year, in the Delta 5 case, climate activists who blockaded oil-train tracks in Everett, Washington, were allowed to present necessity evidence in their jury trial, but the judge ultimately declined to instruct the jurors to consider it. The jury convicted them of trespassing, but acquitted them of more serious charges. More recently, in the West Roxbury case in Boston earlier this year, a dozen climate activists (including DeChristopher and Karenna Gore) who disrupted construction of a fracked-gas pipeline through a residential neighborhood were cleared to present a necessity defense, but prosecutors reduced their charges at the last moment to avoid facing expert witnesses in a jury trial. Not to be deterred, Judge Maryann Driscoll acquitted the defendants of civil infractions by reason of necessity. In a current case in Spokane, Washington, activists who blockaded coal- and oil-train tracks have been allowed to present a necessity defense, pending appeal. And in Cortlandt, New York, a group of activists protesting fracked-gas infrastructure have been allowed to use the defense in a bench trial.

And this is not an exhaustive list. “There’s progress being made, some exciting developments,” Skaggs told me. “And frankly, as the climate situation becomes more and more dire, the argument gets stronger and stronger.”

That argument goes more or less as follows. While the legal criteria for presenting a necessity defense vary slightly from state to state, in Minnesota the defendants must show, first, that there is an imminent physical harm. Definitions of what counts as imminent may differ, but in pretrial briefs the defense showed that courts have taken it to mean not only immediate but inevitable or certain to occur. Expert witnesses on climate science, including Hansen and scientists from the University of Minnesota, are prepared to testify not only to the catastrophic global threat of climate change but also local environmental and public-health impacts in northern Minnesota that are already occurring and will only grow worse.

Next, the defendants need to show that the harm caused by breaking the law was significantly less than the harm caused by obeying it. In other words, they’ll argue that the harm of trespassing and minor property damage pales in comparison to the harm of climate change caused by transporting and burning millions of barrels of tar-sands crude, the most carbon-intensive form of oil, each day.

The defense must also show that there was no viable legal alternative to breaking the law; that is, no alternative that one could reasonably expect to be effective. And then they must show a direct causal connection between breaking the law and preventing the harm; in other words, that the defendants had reason to believe that their direct action would be effective—not necessarily all by itself, but that it would effectively contribute to preventing the harm.

This is where it gets interesting. On these latter points, the defense is prepared to call political scientists and legal scholars, such as Princeton’s Gilens and Harvard’s Lessig, whose research shows the influence of large corporations, including the fossil-fuel industry, over policy-makers in the United States, arguing that it’s unreasonable to expect regular citizens to out-lobby the wealthiest industry on Earth in the corridors of government. Meanwhile, expert witnesses like Middlebury’s McKibben and Jamila Raqib of the Albert Einstein Institution are prepared to testify on the effectiveness of civil disobedience and nonviolent direct action in igniting and spurring social movements that have brought profound political change—including in situations where the political system seemed as immovable as ours today.

In an amicus brief for the Minnesota defendants signed by more than a hundred law professors, the authors draw a direct link between the climate-necessity defense and the federal Juliana case going to trial in Oregon, noting that the doctrines involved “underscore the serious constitutional implications of the ongoing climate crisis.” The harms that the Valve Turners are trying to prevent, the authors write, “are matters not of personal political opinion but of constitutional rights and duties.” The government’s failure to protect a stable climate is an abrogation of those rights and duties, and the defendants’ efforts to redress that failure through nonviolent civil disobedience “is part of the American democratic tradition.” Indeed, the defendants “stand in the shoes of the American freedom fighters, the abolitionists, the suffragettes, the civil rights campaigners of the 1960s, and the antiwar protesters that followed,” the authors write. “Criminal trials in which protesters have explained and argued their views are an integral part of that tradition.”

“The core and indispensable function of the necessity defense,” the amicus brief argues, “lies in submitting to a jury of the defendant’s peers the question of whether the defendant’s protest actions were justified by the social, political, scientific, and moral context in which they took place. Jurors are called upon…to act as the ‘conscience of the community.’”

Clearwater County, Minnesota, with a population of less than 9,000, gave 69 percent of its 2016 presidential vote to Donald Trump. The pipeline company Enbridge has a significant presence in the rural county, where, according to Census figures, more than 16 percent live below the poverty line. The major Enbridge Line 3 replacement project, which will cut through the county as it brings more tar-sands crude from Alberta, has met determined resistance from the climate-justice movement and indigenous communities, who have vowed to make the Line 3 fight the next Standing Rock. And Minnesota is among the states where anti-protest legislation has been introduced that would impose severe criminal penalties on anti-pipeline activists, making clear the kind of political forces the fossil-fuel industry has on its side.

This might not seem a jurisdiction where the Valve Turners can expect the most sympathetic jury pool. And yet, as the Climate Disobedience Center’s Marla Marcum told me, the local political atmosphere actually strengthens the argument for bringing the climate-necessity defense to Clearwater County.

“It’s important that the necessity defense is going to be argued in a relatively conservative community where Big Oil and even a particular company, whose pipes were shut down, have a pretty big footprint,” Marcum said. “Because ordinary folks in places like that, people who will be in that jury pool, have not actually had many opportunities to hear the full truth about what’s going on.”

“Very few necessity cases ever get to a jury trial,” Marcum said. “But when they do, there’s so much potential for the jury to be a sort of last bastion of real direct democracy, if the jurors are allowed to hear all of the relevant facts. And even if it’s Trump Country, or whatever labels you want to put on this community, I trust that ordinary folks care about their families, and they care about the future, and they don’t really understand what is being done in their name, right under their noses, every day—because it’s a multimillion-dollar industry to ensure that they don’t know.”

I asked Annette Klapstein, an activist since she was 17 years old, when she joined the movement against the Vietnam War, what she hopes her action and trial will have accomplished.

“We showed what’s possible,” she said. “I’ve heard that from people whose primary fight is perhaps not climate change, people whose primary focus is more indigenous rights or Black Lives Matter issues, police-brutality issues—people who told me, when we saw what you did with very little help, we didn’t know it was possible, and now we do. We can just go and do this. That’s one thing that has come out of this, to inspire people to go ahead and do what needs to be done.”

How does she respond, I asked, to those who contend that it’s too late for actions like hers to make a real difference in the climate crisis—or that it’s naive to think they ever could?

“I think that’s largely an excuse,” she said. “Is it too late? It could be. Absolutely. But what is my alternative to fighting to the end? I’m going to go down fighting, because I don’t know—I can never be absolutely certain it’s too late. I’m going to do what I can to at least lessen the damage for as long as I draw breath.”

“I hope the jury will be open to hearing what the scientists and political scientists have to say,” she told me. “I don’t know if they will. But I went into this accepting the possibility that I could go to prison. I’m completely at peace with whatever outcome we get. Whatever happens, it’s OK. I’m very happy to be able to present our case, both to the jury and judge and to the larger world.”