Like any good performance, a successful day in court requires practice. A lot of practice, says Ben Chagnon, a senior attorney with the environmental law nonprofit Earthjustice.
Chagnon would know: He has argued and assisted with cases up and down the judicial system, and like most seasoned advocates, he uses moot courts — or simulated court hearings — to prepare for oral argument.
“One thing you’re always looking for are people who won’t automatically agree with you, but who will understand the issues, and even understand what the lawyer on the other side is going to argue,” Chagnon says.
Typically, Earthjustice relies on panels of its own lawyers to refine oral presentations before entering a courtroom, Chagnon says. But today, he is grateful to have an additional testing ground for critical environmental law cases: the Environmental Moot Court Initiative at Harvard Law School.
The initiative, which began in 2023 and is part of the Emmett Environmental Law Center, brings together students and experts to help green law organizations prepare for court — bolstering their chances, supporting wider environmental legal strategy, and giving budding environmental lawyers an insider’s view into the profession.
Earlier this year, Chagnon and his Earthjustice colleagues participated in a moot court through the program, which he calls a “real benefit” to eco litigants.
“What they’re doing is a great way to help environmental nonprofits have the same amount of firepower when it comes to the dedicated preparation for oral argument that the government has long had,” he says. “Between the faculty, students, and other experts, the group can offer a lot of ideas, some of which might change the way you ultimately choose to present your case.”
‘No one else does what we do’
Led by Andrew Mergen, the faculty director of Harvard’s Emmett Environmental Law and Policy Clinic, along with clinical instructor Sommer Engels, the initiative is unique. While other law school moot court programs exist, Harvard’s is the only one focused on supporting outside environmental advocates with cases at any stage of litigation in state or federal courts.
“No one else does what we do,” says Mergen, who spent decades leading and working at the appellate section of the Environment & Natural Resources Division at the Department of Justice before joining Harvard Law.
Such a service is critical to advancing environmental law today, Mergen insists.
“The courts have changed a lot over the last few decades,” he says. “I think a lot of the green groups have recognized that, and they’re trying to be more strategic about the cases that they bring, and how they argue them.”
“Our moot courts are tailored toward getting advocates to think about who their audience is, and that’s the audience we’re recreating for them.”
Andrew Mergen, faculty director of Harvard’s Emmett Environmental Law and Policy Clinic
Mergen says that environmental laws and regulations can be dense and complicated, and cases often turn on administrative and procedural issues, making it a particularly thorny area of the law.
“You see that so many of the real issues aren’t strictly environmental,” Mergen says. “Oftentimes, they relate to how you get to court, or what the remedies are. So, you need a lot of different expertise in the room.”
Even judges can have a hard time with these questions, which means that environmental plaintiffs need to work diligently to frame their cases in the right way, Mergen says.
This is where Harvard’s moot court initiative steps in. “Our moot courts are tailored toward getting advocates to think about who their audience is, and that’s the audience we’re recreating for them,” he says.
And it’s not only advocates who benefit from the experience: Mergen says that the moot court sessions are an opportunity for students to learn more about the field — and what practicing law really looks like.
“Many of our students will serve as law clerks in a year or two, and they’re going to be sitting in hearings, and I want them to know how to listen, and how to ask questions,” he says. “And for others, they get a sense of the issues that come up in these cases, how to think about them, and how to win or at least how to lose well.”
A boost for advocates
The process begins when lawyers like Chagnon reach out to Mergen and Engels, who put together a panel of Harvard Law students, faculty, and external subject matter experts to act as judges and interrogators. First, team members read the legal briefs on both sides of the case, then generate a slew of probing — and sometimes critical — questions for the lawyers. On the day of the moot, the team assembles in person and on Zoom for a pretend court session, complete with spectators and a judge.
With so many different perspectives in the room, advocates gain insight into the strongest — and weakest — parts of their case or presentation, Chagnon says.
“The risk, if you’re an organization like ours, is that you populate your moots with attorneys who have worked on the case or are inclined to agree with you,” he says. “Those lawyers are fantastic mooters. But the Harvard program brings a distinct perspective that helps you get to the bottom of some of the pushback you might get in court.”
Mergen and Engels, who also previously served at the U.S. Department of Justice, bring decades of public-sector experience to the table — an asset in an area of law where federal agencies are often the defendants in environmental cases.
“Because of their background at the DOJ, they can help you understand where your arguments could go wrong, or a different direction you could consider,” Chagnon says.
“With the Harvard program, you can get to the bottom of some of the pushback you might get in court.”
Ben Chagnon, senior counsel at Earthjustice
The students also bring an important perspective, he says, striking a kind of Goldilocks balance: knowledgeable enough to ask sharp questions, yet still open to learning more.
“That’s the sort of thing you get in real oral argument,” Chagnon says. “A judge might approach the case from a more generalist perspective, and it can be up to the advocate to help the judge more fully understand the more technical side of the case. So, it’s always helpful to have a generalist perspective.”
And even flawed questions can be helpful, as student Meghna Sinha ’26 learned.
“A lot of times, the ‘dumb’ questions are not actually dumb questions, because they are the first things that are also jumping out to everyone else in the room and maybe, eventually, to the judge,” she says.
Finally, when the practice session is over, it’s time for tough love, as participants offer constructive feedback on the arguments themselves, and on presentation, style, strategy, and more.
“What makes it a particularly good experience is that [Mergen and Engels] are both very kind and warm, but they also play the role of a difficult judge, where they give you skeptical questions, and they’ll push you on them,” Chagnon says. “And after all that, they’re very positive and warm in their feedback, and also very generative in terms of offering solutions.”
Students also offer helpful observations, not only on the attorneys’ responses to questions, but also to the overall arc of their argument, Engels says.
“Afterward, they often give feedback that is spot on, feedback that we wouldn’t get in the heat of the moment, but that takes into account everything that happened during the moot,” she says. “They’re a very important part of the process.”
Out of the classroom and into the courtroom
Mergen says that’s his biggest goal for student participants is to understand what makes for good — and not-so-good — oral advocacy.
“I ask them to really think about things like, ‘What answers did you find convincing? Can you tell the advocate why you found it convincing? What words matter to you?’” he says. “I also want them to see how an advocate pivots from one argument to another, or how, in a difficult line of questioning, the advocate might look for an off-ramp to move the argument to a place where they’re more comfortable. It’s all an important learning experience.”
The students say the moot courts are a way to see how environmental law is practiced in the real world, and how lawyers craft arguments for a variety of audiences.
“Students who choose to participate are asked to come up with a series of questions in reaction to a brief, which allows us to mentally step into the role of judges and forces us to confront the reality of trying to write accessibly about often quite technical and scientific concepts,” says Madison Onsager ’26.
Spencer Weiser ’26 began participating in the moots even before he enrolled in Harvard’s environmental law clinic, and the sessions have quickly become one of his favorite things about law school.
“This initiative has been a fundamental part of my experience at HLS,” he says.
Weiser says the mock courts have not only helped him improve his practical legal skills — how to read briefs, think critically about issues, and construct arguments for the courtroom — they have expanded his knowledge of doctrinal environmental law.
“Students who choose to participate are asked to … step into the role of judges [which] forces us to confront the reality of trying to write accessibly about often quite technical and scientific concepts.”
Madison Onsager ’26
One memorable moot involved an attorney who was defending a regulation in federal court. While the central issue was clearly one with environmental implications, Weiser says there was much more to unpack.
“It was really interesting, because it involved some constitutional law issues, such as the Fourth Amendment,” he says. “It was cool to see the nexus between these non-environmental law issues, such as search and seizure and right to privacy, and the program that the state designed to improve the sustainability of a local industry.”
Sinha, also a law student, says that reading legal decisions isn’t sufficient to understand how cases are put together, or how attorneys think about the issues involved. By contrast, the moots “give insight into the earlier parts of the strategy,” she says.
As just one example, Sinha says she learned how pivotal opposition briefs can be in preparing one’s own oral arguments. “They obviously pull out all of your weaknesses, and that is likely where the court is going to go, too,” she says.
She adds that the moot sessions also reveal to students and advocates alike how arguments can land differently when delivered orally rather than on the page.
“When you’re writing a brief, you have more time to think and write,” she says. “You don’t have as much control over an oral argument, and that can be interesting to see.”
Onsager also says that being part of the sessions has helped her understand what a career in environmental law could look like.
“It was an illuminating experience, one that left me with both a greater understanding of the skill and preparation that goes into oral argument and a feeling that I had been able to contribute to the causes that I care deeply about,” says Onsager.
Sowing seeds of future successes
Mergen and Engels see one final, but not insignificant, benefit of assisting environmental litigants: giving green groups a forum to coordinate and strategize, to capitalize on victories, and to limit losses, all in service of the future of environmental law.
“If you are a public interest organization that does endangered species cases, for example, and you’re afraid you might lose your case, how can you lose it in a way that won’t damage your agenda down the line?” Mergen asks. “How can you lose it so that you can keep bringing these cases in the future?”
That’s an idea echoed by Erika Kranz, an attorney with the Environmental & Energy Law Program, who also previously worked for the Justice Department.
“Of course, we want to win, but we also want to help control losses such that they are not broadly damaging,” Kranz says. “How could this end up on appeal? What about at the Supreme Court?”
After all, cases often have a ripple effect, says Engels, who notes that decisions in environmental cases have historically resulted in important legal precedents for litigants in other practice areas as well.
“Many of the cases that deal with, for example, the powers of the executive branch, such as Chevron [v. Natural Resources Defense Council] and the case that ended it, Loper Bright Enterprises v. Raimondo, percolate up as environmental cases.”
Bringing lawyers together through moot courts helps them think more collaboratively about issues that impact all environmental litigants — and sometimes even those outside the field, Engels says. “It helps the environmental law community not be insular, to cross-pollinate with people who are experts in other areas.”
Ultimately, Kranz believes that Harvard’s initiative is one important way to help level the playing field for environmental law litigants, “because it brings people in with the opposing mindset, people who are particularly well-suited to pick apart arguments and help an advocate prepare for court.”
It’s a point that Chagnon, the Earthjustice attorney, wholeheartedly endorses. “We’re very glad the initiative is here and that the team is so generous with sharing their expertise.”
Want to stay up to date with Harvard Law Today? Sign up for our weekly newsletter.