Seven County, Keystone XL, and NEPA’s Shrinking Horizon

• Pages: 39-45
• Date: 01 March 2026
• Published date: 01 March 2026
• Author: Robert Paterson
• Subject Matter: Administrative & Public Law

MAR/APR 2026 ENVIRONMENTAL LAW REPORTER 56 ELR 10123

AFTER CUMULATIVE EFFECTS:

SEVEN COUNTY, KEYSTONE XL,

AND NEPA’S SHRINKING HORIZON

by Robert Paterson

Robert Paterson, Ph.D., is an Associate Professor of Environmental Planning

at the University of Texas at Austin’s School of Architecture.

Had it been decided a decade earlier, the U.S.

Supreme Court’s 2025 decision in Seven County

Infrastructure Coalition v. Eagle County1 would

have narrowed the environmental review requirements for

one of the most consequential proposed energy infrastruc-

ture projects in U.S. history—the Keystone XL pipeline.2

e decision’s core holding—that agencies need not ana-

lyze environmental eects of “separate projects” outside

their regulatory authority3—directly addresses the most

contested elements of the Ke ystone pipeli ne’s supplemen-

tal environmental impact statements (EISs) over a 10-year

period4: upstream tar sands extraction, downstream Gulf

Coast rening, a nd end-use combustion emissions.5

Under Seven County’s framework, at least two of the

three supplemental EISs required for Keystone XL would

have been fundamentally circu mscribed,6 if not entirely

foreclosed.7 e 2014 nal supplemental EIS’s life-cycle

greenhouse gas (GHG) analysis would have been optional

rather than legal ly required. e court-ordered 2018-2019

supplemental EIS, mandated after Judge Brian Morris

found National Environmental Policy Act (NEPA)8 viola-

1. 605 U.S. 168 (2025).

2. U.S. Department of State, Final Supplemental Environmental Impact

Statement for the Keystone XL Project (2014) (DOE/EIS-0433-S1) [here-

inafter 2014 SEIS]. See also U.S. Department of State, Keystone XL Pipeline

Project, https://www.state.gov/keystone-xl-pipeline (last visited Dec. 20,

2025).

3. Seven Cnty., slip op. at 13 (describing the decision as providing “a course

correction” for lower court NEPA jurisprudence that had expanded NEPA’s

scope beyond what the statute requires).

4. 2014 SEIS, supra note 2 (Executive Summary). See also Indigenous Env’t

Network v. U.S. Dep’t of State, 347 F. Supp. 3d 561, 565 (D. Mont. 2018)

(documenting project timeline).

5. Seven Cnty., slip op. at 3 (“NEPA requires agencies to focus on the envi-

ronmental eects of the project at issue,” not “the environmental eects of

projects separate in time or place....”).

6. e distinction matters, because the Court’s framework does not categori-

cally prohibit such analysis—it renders it optional. As Justice Brett Kavana-

ugh explained, agencies may choose to analyze eects outside their regulato-

ry authority but are not required to do so. Id. at 21. is permissive frame-

work is precisely what would have undermined the legal compulsion driving

the Keystone 2014 and 2018-2019 supplemental EISs. Cf. Indigenous Env’t

Network, 347 F. Supp. at 591-602 (ordering supplemental analysis based

on precisely the type of cumulative eects reasoning that Seven County now

renders discretionary).

7. See Seven Cnty., slip op. at 15-21 (holding that the U.S. Court of Appeals for

the District of Columbia (D.C.) Circuit erred in requiring the agency to ad-

dress environmental eects of upstream and downstream projects “separate

in time or place” from the railway).

8. 42 U.S.C. §§4321-4370h.

tions including failure to ana lyze cumulative GHG eects,9

would almost certai nly have been foreclosed by the Court’s

instruction that agencies need not ana lyze excluded life-

cycle eects or end-use combustion that occur in “proj-

ects separate in time or place” and outside the agenc y’s

regulatory authority.10 In that counterfactual world, the

U.S. Department of State’s role in recommending or issu-

ing a presidential permit for the border-crossing segment

would have been substantially more insulated from GHG-

based challenges, not because the permit itself was beyond

review, but because Seven County would have sharply nar-

rowed the legally required scope of the underlying environ-

mental analysis.11

Beyond these specic procedural consequences, Seven

County reorients NEPA’s scope, curtailing cu mulative

eects analysis by redening it through a jurisdictional

lens, and departs from Robertson v. Methow Valley Citizens

Council ’s12 information-forcing mandate. For fossil fuel

infrastructure projects where the most signicant envi-

ronmental impacts occur upstrea m or downstream from

the infrastructure itself, Seven County severely constrains

climate change-related impact analysis. e U.S. Court of

Appeals for the District of Columbia (D.C.) Circuit has

already applied Seven County to explicitly abrogate Sierra

Club v. Federal Energ y Regulatory Commission (Sabal Trail),

its 2017 precedent requiring downstream combustion

emissions analysis for natura l gas pipelines.13

9. Indigenous Env’t Network, 347 F. Supp. at 573.

10. See Seven Cnty., slip op. at 15-17 (distinguishing permissible analysis of in-

direct eects from impermissible requirements to assess environmental im-

pacts of separate projects outside the agency’s regulatory authority); see also

Andrew Brady et al., Seven County Infrastructure Coalition v. Eagle County:

Top Points, DL A P (June 6, 2025), https://www.dlapiper.com/en/in-

sights/publications/2025/06/supreme-court-nepa-review (explaining that

agencies are not required to analyze the eects of projects over which they

do not exercise regulatory authority, including separate oil extraction and

rening operations).

11. See Indigenous Env’t Network, 347 F. Supp. at 591-602 (vacating State’s 2017

record of decision and presidential permit based in part on failures to ana-

lyze cumulative GHG emissions and to explain its reversal on climate analy-

sis); Indigenous Environmental Network v. Department of State, 132 H. L.

R. 2368, 2372-76 (2019) (describing how Keystone XL litigation lever-

aged NEPA-based climate arguments against State’s analysis).

12. 490 U.S. 332 (1989).

13. Sierra Club v. Federal Energy Regul. Comm’n (Sabal Trail), 867 F.3d 1357,

1374 (D.C. Cir. 2017) (requiring FERC to quantify downstream GHG

emissions from natural gas combustion); Town of Weymouth v. Federal En-

ergy Regul. Comm’n, No. 17-1135, 2018 WL 6921213, at *1 (D.C. Cir.

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