The Supreme Court will hear arguments in Suncor Energy v. County Commissioners of Boulder, a case that could determine whether local governments can hold fossil fuel companies accountable under state nuisance law for climate change impacts, potentially setting national energy policy. The primary focus is on the balance of power between federal and state authorities regarding interstate issues like greenhouse gas emissions. However, the article emphasizes less-discussed aspects of horizontal federalism, which involves constitutional protections that prevent one state from interfering with another's sovereignty and internal affairs. These include clauses such as Privileges and Immunities, Commerce, Full Faith and Credit, Republican Guarantee, and the Tenth Amendment, all aimed at maintaining a balanced relationship among states.
Written locally by qwen2.5:14b on 2026-10-05,
using this article's own text rather than the other coverage of the
same event (that is the story summary below).
The Supreme Court will hear arguments in one of the most consequential cases of the term that some legal commentators have put on par with cases such as Citizens United v. FEC or Dobbs v. Jackson Women’s Health Organization.
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commentators → hear → Organization
In Suncor Energy v. County Commissioners of Boulder, the Justices will decide whether Boulder County, Colorado, can utilize state nuisance law to hold fossil fuel companies liable for all harms allegedly caused by global climate change, effectively setting energy policy for the entire country.
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companies → decide → country
This question has far-reaching effects on our economy and our federalist system of government.
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question → have → government
For example, in the petitioner’s Supreme Court brief, they have argued that the regulation of interstate greenhouse-gas emissions is an issue reserved exclusively for the federal government because any attempt by a state to “redress inherently trans-boundary issues such as global climate change” would intrude on the federal government’s authority to resolve interstate disputes.
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attempt → argue → disputes
But less attention has been paid to a key dimension of federalism that is at stake.
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that → pay → stake
The Constitution explicitly recognizes not only a vertical division of authority between the federal government and the states, but also a horizontal structure governing the relationships among the states themselves.
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Constitution → recognize → states
The Constitution is full of guardrails that keep individual states from disrupting the national order.
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that → keep → order
The Privileges and Immunities Clause bars states from discriminating against citizens of other states.
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Clause → bar → states
The Commerce Clause creates a “national common market,” and courts have interpreted it to forbid states from favoring local businesses over out-of-state competitors or unduly burdening trade across state lines.
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courts → create → lines
The Full Faith and Credit Clause requires each state to respect the public acts, records, and court judgments of every other state.
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Clause → require → state
Even the Republican Guarantee Clause prohibits states from dictating the public policy of other states.
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Clause → prohibit → states
But key to understanding horizontal federalism is the Tenth Amendment, which the Supreme Court has recognized protects states from intrusions into their inherent sovereignty.
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Court → understand → sovereignty
So far, the Court has applied that protection only against the federal government.
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Court → apply → government
But the Amendment’s text protects states against intrusions from other states.
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text → protect → states
The Amendment reserves to “the States respectively” every power the Constitution did not delegate to the national government or prohibit to the states.
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Constitution → reserve → states
To comprehend what powers states retained, it’s important to consider what it meant to be a sovereign nation at the time of the founding.
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it → comprehend → founding
As independent sovereigns, the states were governed by the law of nations, which guaranteed every sovereign the right to “self-government and territorial sovereignty” and mandated “perfect equality of nations.”
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which → govern → nations
That meant that no nation could “rightfully impose a rule on another,” or, as Joseph Story put it, “all the laws made by a sovereign have no force or authority except within the limits of his domains.”
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laws → mean → domains
Moreover, that understanding of each state’s sovereignty did not change following ratification because states kept “a residuary and inviolable sovereignty,” surrendering only what the Constitution expressly took away.
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Constitution → change → what
James Madison, for instance, at the Virginia Convention, expressed the understanding that Virginia could not project its laws beyond its borders absent some constitutional authorization to the contrary.
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Virginia → express → contrary
Yet that is precisely what Boulder is attempting to do.
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Boulder → attempt → what
Its state-law tort claims seek to hold energy producers liable for global harm arising from conduct that occurred wholly outside Colorado.
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that → seek → Colorado
This infringes on its sister states’ sovereign authority to regulate conduct within their own borders and violates the Tenth Amendment.
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This → infringe → Amendment
Under Colorado law, abatement is the primary remedy for public nuisance claims, meaning Boulder could seek an order directing defendants to curtail their out-of-state operations.
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Boulder → mean → operations
Suncor gives the Justices an opportunity to revive and clarify this aspect of our Constitution.
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Suncor → give → Constitution
The Court has repeatedly stated that “No State can legislate except with reference to its own jurisdiction”; that state authority is “bounded by the States’ respective borders”; and that no state may “impose its own policy choice on neighboring States.
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state → state → States
What the Court has never done is tie those statements to a single constitutional home.
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done → do → home
Recognizing that the Tenth Amendment protects state sovereignty from intrusions by other states would bring order to the body of doctrine.
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Amendment → recognize → doctrine
It would also provide a framework for the wave of copycat climate suits now pending in Delaware, California, Illinois, Oregon, and elsewhere, as well as for litigation related to “climate superfund” statutes that Vermont and New York have enacted.
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Vermont → provide → that
This approach also has practical advantages — it rests on the Constitution’s text and aligns with the Supreme Court’s prior precedent.
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it → have → precedent
The horizontal federalism arguments in Suncor have mostly been framed as appeals to “the structure of the Constitution,” offered in support of a preemption theory on the vertical division of power.
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arguments → frame → power
Those arguments are correct, but they rely on purposes and objectives embodied within the Constitution.
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they → rely → Constitution
Members of the Court have long been skeptical of “freewheeling, extratextual” reasoning about purposes and objectives, insisting that rights be “lodged firmly in the text or tradition of a specific constitutional provision.”
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rights → insist → provision
The Tenth Amendment provides that anchor.
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Amendment → provide → anchor
Moreover, the Court has established that private actors, the Tenth Amendment as an affirmative defense to challenge laws that upset our federalist structure, meaning the approach is firmly rooted in current precedent.
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approach → establish → precedent
The Founders created a union of equal sovereigns, not a system in which the most aggressive state sets the rules for everyone else.
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state → create → everyone
When deciding this case, the Justices should keep in mind that the Tenth Amendment prevents states from intruding on one another, not only the federal government from intruding on the states.
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Amendment → decide → states
The Aporia
