The Supreme Court Just Redrew the Map for NEPA Reviews. What Does It Mean for Your Projects?

On May 16, 2025, the Supreme Court handed down a unanimous ruling that effectively tightens the leash on what NEPA requires. For Department of Defense (DOD) planners and other federal agencies focused on mission readiness, this decision could be a game-changer.

But what does a case about a railroad in Utah have to do with building a new training range at Fort Bragg or expanding a pier in Norfolk? Let’s break it down in plain English.

1. The Story: A Railroad, Some Oil, and a Legal Showdown

Imagine you want to build a new road to connect a remote factory to a major highway. Your job is to analyze the impact of building that road: the land it crosses, the streams it bridges, the noise from construction.

Now, what if someone argued that you must also analyze the environmental impact of every product that will ever be made at that factory and shipped down your new road? And then the impact of consumers using those products? The analysis would spiral into infinity.

That’s the core of what the Supreme Court just addressed in Dep’t of Transportation v. Eagle County, Colo. (“Seven County” case). A federal board approved a new railway to transport oil out of a basin in Utah. They studied the impacts of the railroad itself, but a lower court said, “Not good enough. You also have to study the global climate impacts of burning all that extra oil.”

The Supreme Court unanimously said, “No, that goes too far.”

2. The New Rule of Thumb: The “Stone in the Pond” Principle 

The Supreme Court’s opinion brought the focus back to a classic legal idea: proximate cause.

Think of it this way: If you drop a stone into a pond, NEPA requires you to analyze the splash and the immediate ripples. You are responsible for those direct, foreseeable effects.

This new ruling clarifies that you are not responsible for analyzing a hurricane that forms on the other side of a continent a week later. The connection is simply too remote. The Supreme Court stated that an agency only needs to study effects that have a “reasonably close causal relationship” to its specific action.

Building the railroad is the stone. The burning of oil somewhere else, by someone else, is the hurricane.

3. Wait—Didn’t the Supreme Court Just Say Agencies Have Less Power?

Here’s where it gets interesting.

Back in February 2024, Scout’s monthly blog previewed a major legal shift: the Supreme Court was deciding whether to take away a long-standing rule that let federal agencies interpret vague laws. That rule—called the Chevron Doctrine—had been around for 40 years. It basically said, “If the law isn’t clear, trust the agency’s interpretation.”

In June 2024, the Supreme Court officially got rid of that rule. It said courts—not agencies—should now decide what a law means. That’s a big deal.

Then, nearly a year later, in May 2025, the Supreme Court issued the Seven County case. This time, the Supreme Court said it would still respect how agencies apply the law to the facts of a specific project—like how far an environmental review should go under NEPA. That might sound like a contradiction.

So what’s going on?

The key is this: There’s a difference between interpreting a law and applying it.

The Supreme Court said agencies don’t get the final word on what a law means anymore—but if they apply the law reasonably to the facts of a project, courts will still generally respect that. In Seven County, the Supreme Court didn’t let the agency redefine NEPA, but it did support the agency’s judgment on how far to go with the analysis.

For NEPA projects, the takeaway is simple: NEPA decisions grounded in solid facts and clear reasoning are still likely to hold up in court. Even as courts take a harder look at how agencies interpret the law, they remain willing to defer to agencies that show they’ve done their homework and made thoughtful, evidence-based decisions.

4. What This Means for Your Project: Three Tangible Examples

This isn’t just a legal theory. It has direct, on-the-ground consequences for the projects you manage.

1. Focusing on the Footprint of the Base, Not the Whole Supply Chain.

• • Old Problem: When modernizing a port, a project could get bogged down analyzing the carbon footprint of every ship that might ever dock there, or the global supply chains they support.
  • New Reality: The NEPA review can now more confidently focus on the direct impacts of the port’s construction and operation—dredging, local air quality, marine life—without being forced to analyze the entire life cycle of global commerce. This makes the scope more manageable and the timeline more predictable.

2. Streamlining a New Training Range.

• • Old Problem: An Environmental Impact Statement (EIS) for a new live-fire training range might face challenges demanding an analysis of the “downstream” manufacturing impacts of the munitions to be used, or the long-term carbon footprint of the military vehicles that will access it.
  • New Reality: The focus is now squarely on the mission-critical action: building and operating the range. Your NEPA documentation will analyze noise impacts on the surrounding community, effects on local wildlife, and land disturbance. It’s a more defensible, focused, and efficient process.

3. Clearing the Path for Energy Projects.

• • Old Problem: A proposed microgrid or backup power generation project on base could be challenged to analyze the full “cradle-to-grave” impact of the fuel source.
  • New Reality: This ruling strengthens the argument that the analysis should focus on the direct effects of the power facility on the installation itself, helping to accelerate projects crucial for mission assurance and energy independence.

5. A Front-Row Seat to a Landmark Case

The nuances of this case are fascinating, and I had the opportunity to hear a deeper dive at this year’s National Association of Environmental Professionals (NAEP) conference. It was a privilege to hear directly from the legal and strategic minds behind this victory. A huge shout-out to attorneys Fred Wagner and Jay Johnson, along with the client himself, Mark Michel of the Integrated Rail and Resources Acquisition Corp, for their fantastic presentation. Their firsthand account of the decade-long process underscored the importance of a resilient, forward-thinking NEPA strategy.

6. Our Role in This New Landscape

This Supreme Court decision is a powerful new tool, but it’s not a “get out of NEPA free” card. It provides clarity, but it also creates new legal and strategic lines to navigate. Opponents will now look for new ways to challenge projects, probing for the exact boundary of that “reasonably close causal relationship.”

This is where we come in.

At Scout, our job is to handle this complexity from beginning to end. We lead NEPA projects from inception and do the rock-solid NEPA analysis that accounts for this new legal landscape. We worry about the ripples in the pond so you can focus on the mission.

Need help planning for your next NEPA project? Reach out to us at hello@scoutenv.com.