The Rule of Five and the Unmaking of U.S. Climate Law

In 2007, I remember reading the headlines about Massachusetts v. EPA. Five justices — by the slimmest possible margin — had ruled that greenhouse gases are air pollutants under the Clean Air Act. It was a victory not just for environmental law, but for science. As a science educator and someone who has spent a lifetime helping students world-wide think globally, I saw this decision as a moment when the law finally caught up with the scientific reality.

But now, in 2025, we are watching the very foundation of that ruling being dismantled. The Trump administration has announced plans to revoke the EPA’s 2009 endangerment finding — the scientific determination that greenhouse gases like carbon dioxide and methane threaten public health. If they succeed, they won’t just halt climate progress. They’ll sever the legal link between science and policy that took decades to build.

This is not just a rollback. It’s a repudiation of science itself.

What the Science Said — And Still Says

In 2009, the EPA issued the endangerment finding after reviewing thousands of peer-reviewed studies. As someone who taught generations of students to evaluate evidence, I was heartened to see the agency respect the scientific method. The finding stated unequivocally: greenhouse gases are destabilizing our climate, harming our health, and threatening future generations.

I used that document in my writing and research.. It was a teachable moment — proof that science could inform democratic policy. The finding became the legal trigger for regulating emissions from cars, power plants, and industry. It even underpinned America’s entry into the Paris Agreement. Obama’s administration signed on to the Paris Agreement, joining all countries except for two. Trump pulled the U.S out of the Paris Agreement in his first and second terms. Biden got us back to the Paris accord after Trump’s first term.

.Science did its job. Policy followed.

But now, politics is trying to erase the science.

The Rule of Five, Revisited

Richard Lazarus’s The Rule of Five tells the gripping story of how that 5–4 Supreme Court ruling came to be. It’s a story of persistence, of lawyers and scientists working together to make climate change a legal issue, not just an environmental one.

The most chilling part of Lazarus’s book comes after the 2016 election, when Joe Mendelson — the man who started the case — wakes up afraid that all they fought for would be undone. He was right to worry.

Trump’s EPA isn’t just tweaking regulations. By trying to revoke the endangerment finding, they’re aiming to invalidate the very logic of Massachusetts v. EPA. If there’s no finding that greenhouse gases endanger public health, the Clean Air Act’s mandate to regulate them disappears.

It’s like removing the battery from a smoke detector, then claiming there’s no fire.

A Moment of Scientific Reversal

Let’s be clear: the science hasn’t changed. If anything, the evidence for climate disruption is stronger than ever. July 2025 was the hottest month in recorded history. Wildfires, floods, and extreme weather events are escalating. Air quality is worsening. Cities in the U.S. and Canada are experiencing worsening air from smoke from fires in both countries.

Our public health is at greater risk — not less.

So how can the EPA now claim that greenhouse gases no longer endanger us?

They can’t — not credibly. But in this administration, political goals often override empirical evidence.

As a Science teacher, I find this alarming. As a citizen, I find it unacceptable.

The Political Side of the Climate Crisis

Lazarus ends his book with a sober truth: legal victories are fragile. Courts can open doors, but only elections can keep them open. And we are living proof of that.

During Obama’s years, we saw science-based policy take root. Under Trump, we are witnessing an anti-scientific counter-revolution — one that treats climate science as optional, and regulation as a partisan nuisance.

This is not just about the Clean Air Act. It’s about whether facts still matter in policymaking.

Threatenig the Heart of Education, Democracy, and Stewardship

I’ve spent decades teaching science education — encouraging inquiry, evidence, and critical thinking. The very idea that a federal agency might discard overwhelming scientific evidence because it’s politically inconvenient strikes at the heart of what education, democracy, and stewardship mean.

I also helped lead the Global Thinking Project, connecting students across continents to collaborate on environmental challenges. We taught them that climate action was both a scientific necessity and a human responsibility. What do I tell those students now?

• That their government no longer believes what the data shows?
• That public health is negotiable?
• That our legal system can be reengineered to ignore science?

What Happens Next?

The Trump EPA’s move will be challenged in court — and it should be. The Administrative Procedure Act requires agencies to explain reversals with reason and evidence. The original endangerment finding was backed by volumes of science. Can this new version meet that bar? Doubtful.

But we can’t leave this to the courts alone. Scientists, educators, and citizens must raise our voices — in classrooms, in public hearings, in the voting booth.

The Rule of Five is a reminder of how precarious progress can be. It took years of work, one strategic lawsuit, and five justices to make climate law in the U.S. possible.

It may take just one administration to tear it all down.

This is not just a legal dispute. It is a test of our commitment to evidence-based governance — and our courage to defend it.