Despite its prominence in political discourse, climate change has been the focus of relatively little stand-alone legislation. The 2022 Inflation Reduction Act contains the only significant federal climate provision to date, but the majority of its green energy subsidies and tax incentives have since been rolled back (Sidley Austin 2025). Other major economy-wide climate proposals have failed in Congress, and most enacted climate-related measures have been modest provisions embedded within broader infrastructure or energy bills.

On the regulatory front, however, climate policy has been much more active. Over the past two decades, federal agencies have proposed and finalized a wide array of rules governing greenhouse gas (GHG) emissions from vehicles, power plants, and other sources. Many of these rules have been revised or repealed by subsequent administrations. Nearly all of this authority traces back to a 2009 determination by the Environmental Protection Agency that GHGs endanger public health and welfare under the Clean Air Act (CAA).

This finding followed the US Supreme Court’s 2007 decision in Massachusetts v. EPA, which rejected the Bush administration’s claim that it did not have the authority to regulate GHGs and held that GHGs fit the CAA’s definition of “air pollutants.” The finding required the EPA to determine whether GHGs endanger public health and welfare and, if so, to regulate them. In 2009, the Obama administration concluded they do, setting in motion subsequent regulation of GHGs under the CAA.

Given the stakes, the endangerment finding has been contested ever since. On the stump in 2016 and promptly after returning to the presidency in 2025, Donald Trump made clear that repealing it would be a priority of his administration. Accordingly, in February the EPA announced its final decision to repeal the finding. The battle is far from over, however: Environmental groups have filed suit challenging the rescission.

Values and Politics

From a political economy perspective, the legal and scientific disputes are largely secondary. For many policymakers and commentators, views about the validity of the endangerment finding tend to track prior beliefs about the severity of climate change and the appropriate policy response. The finding itself represents both those underlying disagreements and Congress’s inability or unwillingness to resolve them through legislation. Without a comprehensive climate law, the issue shifted to existing statutory authority and the courts.

The debate over the endangerment finding has therefore played out in legal and scientific terms because those are the channels available under the current framework. But repealing the finding does not resolve the deeper differences in values and priorities that drive conflicting views of climate change. Without a broader shift in political incentives or a willingness to compromise, there is little reason to expect long-term climate policy outcomes to change significantly, with or without the endangerment finding. Democratic administrations will continue to pursue aggressive climate policies where they can; Republican administrations will continue to constrain and dismantle them.

In the meantime, however, this dynamic has real consequences. The CAA was designed to regulate local, conventional air pollutants with scientific characteristics and effects that differ substantially from those of GHGs. This mismatch means that climate regulations within the current statutory framework have imposed significant costs and economic inefficiencies (Lesser et al. 2025) while delivering limited net climate benefits (Loris et al. 2025). Moreover, relying on legal and administrative avenues to implement climate policy makes those policies highly susceptible to shifts in political leadership, allowing them to be repealed almost as easily as they are enacted. The result is substantial policy uncertainty, which discourages long-term investment and complicates economic planning.

These downsides should serve as a cautionary tale for both supporters and opponents of the endangerment finding. The finding emerged as a workaround to legislative impasse, stretching existing law to address a new and complex problem. In doing so, it has contributed to regulatory instability and political polarization over climate policy. But repealing the finding does not solve those underlying problems. As easily as one presidential administration can conclude that GHGs do not endanger public health and welfare, the next can conclude the opposite. As legal scholar Jonathan Adler has argued, if the Trump administration truly seeks to remove the EPA’s authority to regulate GHGs, it will ultimately require Congress to reform the underlying statutory framework (Adler 2025b).

The key takeaway is that, until Congress confronts climate policy directly, the fight over the endangerment finding—or something like it—will continue. Even if some degree of legislative compromise were possible, disagreements over the proper scope of climate policy will remain. But comprehensive legislation might at least reduce the regulatory inefficiency and uncertainty that stems from repurposing existing laws and relying on executive action alone.

Of course, it is probably unrealistic to expect such a contentious legislative breakthrough anytime soon. In the meantime, policymakers would be better served pursuing incremental improvements in energy and environmental policy, such as reforming permitting processes or advancing policies that spur technological innovation to mitigate and adapt to climate risks.

• Adler, Jonathan H., 2011, “Heat Expands All Things: The Proliferation of Greenhouse Gas,” Harvard Journal of Law & Public Policy 34(2): 421–466.
• Adler, Jonathan H., 2025a, “Climate Liberalism and Decarbonization,” Iowa Law Review 110(5): 1987–2013.
• Adler, Jonathan H., 2025b, “The EPA Announces a Fool’s Errand: Reconsidering the Endangerment Finding,” Rea​son​.com, March 12.
• Conservative Coalition for Climate Solutions, 2023, “Ch. 2: Permitting,” The Climate and Freedom Agenda, August.
• Kemp, David, 2025, “DOE’s Grant Terminations and the Role of the Government in Energy R&D,” Conservative Coalition for Climate Solutions, October 28.
• Kemp, David, and Peter Van Doren, 2025, “How Should We Value the Future?” Regulation 48(4): 36–46.
• Lesser, Jonathan, Frits Byron Soepyan, Brent Bennett, et al., 2025, “Assessing the Costs of Regulations to Reduce CO2 and Other Greenhouse Gas Emissions,” National Center for Energy Analytics, May 16.
• Loris, Nick, Philip Rossetti, Chung-Yi See, et al., 2025, “Cost-Effectiveness of Climate Regulations Depends on Non-Climate Benefits,” working paper, Cornell University, March 14.
• Sidley Austin LLP, 2025, “The ‘One Big Beautiful Bill’ Act—Navigating the New Energy Landscape,” Sidley Update, July 15.