One of the most important environmental lawsuits in history began in a rocking chair in Joe Mendelson’s nursery, as his daughters, 1 and 3 years old, drifted off to sleep. This was long before Mendelson became senior counsel for Tesla, back during the Clinton administration.

“Raising them as little children, I would sometimes be in their bedroom in a rocking chair either trying to put them to bed and sit with them and kind of read over legal work, including this petition,” says Mendelson. “So it’s, in some ways, the third child that was born at the time.”

Mendelson worked for a D.C.-based environmental non-profit called the International Center for Technology Assessment, and he wanted to force the Environmental Protection Agency to begin regulating greenhouse gas emissions under the Clean Air Act, something Congress had never foreseen when it passed the statute in 1970.

It was an enormous ask, and the stakes were huge: he wanted the executive branch to go around an intransigent Congress to do something about climate change. 

Now, 20 years later, a coalition of states and environmental organizations have sued the Trump administration to block its proposed rollback of the Obama administration automotive fuel efficiency standards. Should the lawsuit reach the Supreme Court, the case could reverse, or adversely modify, the landmark 2007 ruling that began in Mendelson’s nursery: Massachusetts v. EPA.

Filed last week, the complaint stands out, even among hundreds of environmental actions filed against the Trump administration. “It will tell us how environmentally destructive the court is willing to be,” says Ann Carlson, at the UCLA school of law.

It’s one of a pair of lawsuits advancing through the courts—the other involves the Trump administration’s repeal of Obama’s so-called Clean Power Plan—that have the potential to reshape a legal precedent that has been called “as close as we will come” to a “Brown v. Board of Education for the environment.”

Massachusetts v. EPA declared that greenhouse gases are pollution under the definition set out by one of the nation’s oldest and most successful environmental laws, the 1970 Clean Air Act. It determined that if the executive branch wanted to do so, it could confront one of the greatest challenges of the 21st century with one of the most celebrated laws of the 20th century.

To fully understand the issues that could come before the court and its new conservative majority, as well as the court’s range of options, requires understanding how we got to this point, and what the ramifications could be.

And to fully understand that requires a history lesson that could begin in Mendelson’s nursery, or in 1998, when EPA administrator Carol Browner publicly crossed swords with House Majority Whip Tom Delay, a Texas Republican, over whether she believed her agency had the authority to combat climate change.  

The Clean Air Act and Carbon Pollution: The Workaround

The legal debate over whether greenhouse gases could be regulated using the Clean Air Act had begun during the Clinton years. The law’s broad definition of pollution—anything that “may reasonably be anticipated to endanger public health or welfare”—represented the tantalizing possibility that environmentalists could deploy a workaround if Congress wasn’t willing to pass a specific climate change law. 

When Delay asked Browner during a House Appropriations subcommittee hearing in 1998 if she believed she had the authority, she responded that the agency would produce a memo asserting they did.

This memo, combined with the fact that the Clean Air Act— inspired by the lawsuits strategically wielded by the Civil Rights movement—was the first law to explicitly include a citizen’s right to sue, presented an opening for activist environmental lawyers like Mendelson. 

Before then, he says, “The Environmental Protection Agency was looking at traditional pollutants, but whenever you mentioned greenhouse gases, and regulating those from the tailpipe of a vehicle, the EPA kind of avoided the subject.” 

Even after Delay had drawn Browner out on regulating greenhouse gases, the big environmental groups didn’t want to force the issue in 1999, because they were looking ahead to Al Gore running for president.

Still, Mendelson and the tiny Center for Technology Assessment were itching for progress. So, they filed a petition asking the EPA to regulate carbon emissions from the tailpipes of cars.

At first it seemed like this gambit was going to work. The Clinton administration called Mendelson in for a meeting and told him they were going to use this threat of a lawsuit as a launchpad for their own plans on greenhouse gases, but then Bush was inaugurated president and the petition was left in limbo. 

It didn’t stay there for long, though. 

‘The Equivalent to Flipping the Bird’

During the hotly contested 2000 presidential campaign against Gore, Bush had actually declared “we will require all power plants to meet clean-air standards in order to reduce emissions of sulfur dioxide, nitrogen dioxide, mercury and carbon dioxide within a reasonable period of time.” 

As his EPA administrator, he appointed New Jersey governor Christine Todd Whitman, who according to Richard Lazarus, author of The Rule of Five: Making Climate History at the Supreme Court, was “presidential timber” and “a household name in the United States back then.” 

“Most people who were watching this, including environmentalists, thought the Bush administration was going to be the hero on the climate issue,” says Lazarus. 

This hopeful period was brief. Shortly after his inauguration, in response to lobbying from fossil fuel-related industries and to members of Congress from the states where those industries were particularly powerful, the Bush administration crafted a letter completely disavowing Bush’s campaign pledge on greenhouse gases. 

Todd Whitman declined to be interviewed for this piece, but in 2007 she told Frontline that “the way it happened was the equivalent to flipping the bird, frankly, to the rest of the world, on an issue about which they felt so deeply.”

This was the moment that caught Jim Milkey’s attention. While today, he’s an associate justice on the Massachusetts Court of Appeals, back in 2001 he was taking a year off as a lawyer with the environmental department of the Massachusetts Attorney General’s office. He was in Denmark with his family gaining a very European perspective on climate change.

“I did make a decision that when I came back, which was July of 2001, I would do everything in my power to try to carve out a state role in this area,” says Milkey, who began hatching a plan to force the federal government to take some sort of federal action on climate change. “Our job was to sue people, to defend state officials when they got sued. There’s an old expression that if your only tool is a hammer, every problem starts to look like a nail. And we had to develop our nail and our hammer.”

At first, Milkey and a small crew of lawyers from other like-minded states got to work crafting their own legal argument, a so-called mandamus case based on a common law public nuisance complaint—the same concept that led to the regulation of lead pollution. Before long, though, they became aware of Mendelson’s motor vehicle petition. 

And this is where Jim Milkey—who had a hammer—found his nail. 

In 2003, Milkey and Mendelson decided to combine their hitherto separate efforts. Both agreed that Massachusetts would make a better lead plaintiff (though “in doing so, you know, frankly, we probably relegated ourselves to a footnote in the story,” Mendelson admits). 

When the Bush administration released their response to the petition, Milkey pounced, and a coalition fell in behind him. In all, 12 states and 30 environmental groups joined together on one case.

’Heated and Difficult’

That coalition was first handed a defeat by the D.C. Circuit Court of Appeals. 

It was a three-way split-decision: one judge sided with the petitioners and another sided against them, but the third believed they didn’t have standing to sue over damages caused by climate change.

This meant that, should they appeal to the Supreme Court, the stakes would be even higher. If they lost, not only would greenhouse gases not be considered a Clean Air Act pollutant, but also the wording of such a loss at the Supreme Court could sharply curtail any future ability to sue. 

“I faced enormous pressure from the environmental groups to throw in the towel at that point, and there the head of [the Natural Resources Defense Council] was calling me from New York, telling me things like the future of the environmental movement was on my head,” says Milkey, “It got extremely heated and difficult.”

But in the end Milkey and those who agreed with him prevailed. First they asked for a rehearing en banc, before the full D.C. circuit. That request was denied, and so they decided to go all the way to the top.

Milkey wrote a draft of an appeal to the Supreme Court. His argument was technical, internationally-oriented, science-based and focused on CO2 as pollution. It was a fine document if its audience were donors to environmental groups. “Jim’s draft was the one time there was consensus among all the states and environmentalists … and that’s why Jim’s draft was terrible,” says Lazarus. 

And so Milkey asked a former colleague, Lisa Heinzerling, for help. Then (and again now) a professor at Georgetown University Law Center, Heinzerling had been a clerk for Supreme Court Justice William Brennan prior to joining the Massachusetts Attorney General’s office and understood how to craft an argument that could get the Supreme Court’s attention. 

The enormity of this job is a little hard to overstate. The EPA was created in 1970, and when Heinzerling took over writing the briefs for Massachusetts v. EPA, it was 2006. According to Lazarus, in that timespan, the Supreme Court had never taken a case in which an environmental group was asking the justices to reverse a lower court and order the EPA do something. Never. 

Heinzerling refocused a case that the environmental movement wanted to be about climate change and made it a case about something which was catnip to the justices of the Supreme Court: separation of powers. 

In its initial response to Joe Mendelson’s petition, the EPA listed seven reasons for declining to regulate—including that they did not believe greenhouse gases to be pollution under the Clean Air Act, that the National Highway Traffic Safety Administration already regulated vehicle fuel efficiency, and that they didn’t want to interfere with the president’s strategy at international climate talks. 

Heinzerling calls this “a seemingly random list of reasons why it didn’t want to regulate.” 

The list did include an explanation that was generally considered to be legally sound: the Clean Air Act allows the EPA broad discretion over when it chooses to regulate any given pollution. But how much discretion did the executive branch have? Unlimited discretion? Wasn’t that tantamount to saying, the President can ignore Congress?

Heinzerling found inspiration in a story from 1853, written by Herman Melville. “I opened the new version of the cert petition with a quote from ‘Bartelby the Scrivener,’ who famously says, when asked to perform his job, ‘I would prefer not to,’” she explains.

In June of 2005, Heinzerling’s petition was accepted. 

Her skill in writing the petition, and the briefs that came after, led to intense division among the petitioners. Two factions formed, one that wanted Heinzerling to argue the case before the Supreme Court, and a second that wanted to stick with Milkey. 

In the end, the Massachusetts Attorney General stepped in and declared that, since technically Heinzerling had been hired as a special assistant Attorney General, it was up to him to choose who would argue the case, and he chose Milkey. 

Heinzerling wrote a letter to the coalition of lawyers, withdrawing herself from consideration. She requested that in exchange, she not be submitted to any further four-hour conference calls in which she was given line-by-line edits to her drafts. 

“There were moments,” Heinzerling says, “where I thought, ‘I wonder how this would be going if I were a guy?’”

The rancor destroyed the personal relationships of many of the advocates. “They weren’t speaking to each other during the last sort of two months of the case,” says Lazarus. “They actually haven’t spoken to each other, many on the team, since October 2006.”

Lazarus was present on the day of the oral arguments, and overheard when a senior lawyer from the Sierra Club—who had previously called Milkey and asked him to step aside—walked up to Milkey in the lobby of the Supreme court and said, “Jim, your job today is to make me look like the biggest asshole in the world.”

Mendelson and Heinzerling sat at the counsel’s table with Milkey. Mendelson remembered being so close to the justices on the bench that at one point, “a little bit of spittle” came out of one of their mouths and “landed on my paper.” 

The Road to Paris

In the end, Milkey argued masterfully before the bench. Lazarus would come to conclude that he had “tamed” Justice Antonin Scalia, at one point correcting Scalia when he had asserted that seven percent of total carbon dioxide emissions in the U.S. were attributable to automobiles. It was actually six percent, Milkey said.

“All the books on Supreme Court practice say never, ever, interrupt a Supreme Court justice unless it’s really important,” Milkey says. “And frankly, I think I shocked him at that time because I was correcting him against our interest. And he realized that he, you know, he was facing someone who was not trying to pull the wool over his eyes.” 

In the end, though, it wasn’t Scalia who played the pivotal role in the argument, but Justice Stephen Breyer. In questioning the EPA’s lawyer, Gregory Garre, Breyer was intently focused on the “laundry list” of reasons the EPA had cited in its refusal to regulate. He pointed out that the agency had said all of the considerations (which he pronounced with an emphasis on the plural “considera-SHUNS”) were justified. Implying the agency believed they were all legitimate, even those that made it seem as though the agency was free to ignore Congress. 

Breyer suggested, in his questioning, the EPA erred in citing all of its reasons—plural—for declining to regulate. The fate of this decision, and the future of climate policy in America, had come down to the letter S. 

The high court ruled in favor of the states and environmental groups. The decision was five to four, with the justices appointed by democrats joined by Justice Anthony Kennedy as the swing vote. 

It was that “laundry list” of justifications, which Breyer had zeroed in on, that sank the agency. Justice John Paul Stevens wrote in the majority opinion that “EPA has offered no reasoned explanation for its refusal to decide whether greenhouse gases cause or contribute to climate change. Its action was therefore ‘arbitrary, capricious … or otherwise not in accordance with law.’” 

The ultimate import of the decision was quite narrow, initially. The judges did say that greenhouse gases seem to meet the EPAs definition of pollution, and they did say that Massachusetts was suffering harm because of climate change. But all they said beyond that was that the EPA had to go back and apply proper, legal reasons if they were going to decline to regulate. 

Still, despite the very narrow technical meaning of the decision, its language was grandiose. “In a larger sense, this was the court putting its imprimatur on the problem,” says Milkey. 

It had declared that climate change was real, and it was already causing harm. 

The Endangerment Finding

Almost two years exactly after the Supreme Court ruled in Massachusetts v. EPA, the new administration of President Barack Obama issued a technical document that declared six greenhouse gases “pollution”: the endangerment finding.

Its issuance marked a key moment in the debate on climate change that has loomed as a target of conservatives ever since.

The administration used the endangerment finding to craft new fuel efficiency standards for cars and trucks, and regulations on new power plants that burn coal and natural gas. Finally, in 2013, the Obama EPA took a politically risky step: they set in motion a plan to use the Clean Air Act to reduce carbon emissions from existing US power plants, called the Clean Power Plan. 

With all of this in their pocket, the Obama administration went to the United Nations, and submitted its commitment to the Paris Accords. That commitment was based almost entirely on a forty-five-year-old law—the Clean Air Act—and the authority affirmed in Massachusetts v EPA. 

So in a very concrete way, a story that started in a young lawyer’s nursery—writing while his children tried to sleep—seemed for a while like it would end with the most ambitious international climate agreement up to that point. 

The Perils of Plan B

However, using a law that was written without global warming in mind as your primary legal tool to combat global warming is fraught, as the legal challenges that have plagued Obama era carbon regulations that were the bedrock of it’s Paris commitments show. 

Under the Clean Air Act, any polluter that emits either 100 or 250 tons of a given pollutant per year is required to get a permit to operate. While this threshold made sense for sulfur emitters and steel mills, “a hundred tons of CO2, is not much,” says Janet McCabe, who was the Obama official who spearheaded the creation of the Clean Power Plan.

This low threshold meant that a Clean Air Act permit could be required for apartment buildings or malls or schools. “The Clean Air Act couldn’t possibly have contemplated that thousands and thousands of new types of non-industrial sources would have to get Clean Air Act permits,” says McCabe.

The Obama administration’s proposal to solve this problem—a phased-in approach in which they would have started by multiplying that threshold by 1,000, starting with the largest emitters and work their way down gradually—landed them back in the Supreme Court, where they were dealt a defeat in Utility Air Regulatory Group v. EPA.  

“They said we, the Supreme Court, are not willing to stand on the dock and wave goodbye to EPA as it engages on a multi-year voyage of discovery and decides what it really wants to do,” explains Justin Schwab, who was deputy general counsel in the Trump administration’s EPA until last year. 

Similarly, the Clean Air Act mandates that “existing sources” deal with pollution by installing technologies to clean up their emissions — like a scrubber installed in a smoke-stack. The Obama administration argued that they could interpret the term “source” to refer to the entire electric grid, and the technologies to clean up that source could include things like renewable energy.

Critics of the regulation found that to be a stretch.

“The Clean Power Plan could never have been met by anything that could be done at the level of individual plants,” says Schwab, explaining that it would have required states to “shift away from fossil fuel generation of electricity towards solar and wind generation of electricity.” 

And it may be that the Supreme Court thought it was a stretch, too. In an unprecedented decision early in 2016, the Supreme Court issued a stay, halting the implementation of the rule, a move that showed the court’s five conservative justices believed the regulation was illegal in some way.

The Trump administration has since repealed the Clean Power Plan and issued a replacement rule, called the Affordable Clean Energy rule, which focuses on technologies installed at individual coal-fired power plants to make the combustion of coal more efficient. The EPA forecasts it will reduce greenhouse gas emissions by between .7 and 1.5 percent by 2030. 

“The Trump administration has adopted this program that really is designed to establish the limits of what EPA’s regulatory authority is under the Clean Air Act,” explains Jeff Holmstead, who ran George W. Bush’s EPA Office of Air and Radiation.

Challenges to the ACE rule are already before the D.C. Circuit Court of Appeals. While no date has been set for oral argument, briefs were due at the end of April. This means that the possibility looms that this case, or the challenge to the motor vehicle rules filed last week, might wind up before the Supreme Court. 

“The Supreme Court does not hand out cert like candy, but it’s entirely reasonable to expect that these issues will come before it for a fifth, and potentially final, statement in this saga,” says Schwab.

Ann Carlson of UCLA says while it’s possible that today’s Supreme Court may reverse Massachusetts v. EPA altogether, at the very least, the court will weigh in on how powerful the Clean Air Act really is as a way to regulate climate change. 

“The Obama administration did it in a really aggressive way. The Trump administration is doing it in the least environmentally protective way possible. Which one is okay?” she says.

Massachusetts v. EPA: A Legacy Still Being Written

Even the most fervent advocates of the Clean Air Act acknowledge that it is not an ideal climate law. “It would be probably a good bit faster if Congress could agree on something meaningful and put that in place,” says Janet McCabe. 

But it’s worth pointing out that the Clean Power Plan was not terribly ambitious. Indeed, even though it was repealed, the country is on track to meet the goals it set out. The Trump administration has highlighted this extensively in the justification of its coal plant rules. 

“The ACE rule and the Clean Power Plan would therefore not end up being much different in terms of the overall profile of the emissions from the sector anticipated,” says Schwab.

In the meantime, the backlash to the Trump administration’s abandoning of the Paris agreement has united the left around a substantially more ambitious climate agenda than had been contemplated in 2016. And perhaps motivated by enduring and growing bipartisan concern over climate change the right has again begun to take its own tentative steps into the climate policy arena.

“The legacy of Massachusetts v. EPA is still being written, and I don’t think we will know the true legacy for years into the future,” says Holmstead. If the finding of the case is repealed or substantially curtailed “there will likely be much more pressure on Congress to develop something that actually will be longer lasting and won’t change from administration to administration. And I think that’s a very important thing.”

Sam Evans-Brown is the host Outside/In, a podcast and radio show produced by New Hampshire Public Radio about climate and environmental issues. Outside/In has won multiple awards including a National Edward R. Murrow award, and the 2018 Overseas Press Club award for best environmental reporting in any medium.