Fact check: Which attorneys or firms led separation-of-powers litigation against the president in 2020 and 2021?

1. Who fronted the blockbuster 2020 separation‑of‑powers fight and what did they argue?

The major 2020 case identified is Seila Law LLC v. CFPB, where Kannon K. Shanmugam is recorded as lead counsel for the petitioner challenging the Consumer Financial Protection Bureau’s single‑director structure as incompatible with the Constitution’s separation of powers. The United States defended the agency through Solicitor General Noel J. Francisco, and the matter attracted high‑profile amicus participation from figures such as Paul D. Clement. Law firm involvement for the petitioner included Paul, Weiss, Rifkind, Wharton & Garrison LLP, signaling a traditional private‑practice challenge to an independent agency’s removal protections in 2020 ^{[1] [2]}. This litigation was framed as a constitutional challenge to agency design rather than a direct suit naming the President.

2. Which lawyers represented states challenging executive action in 2021, and how does that fit the separation‑of‑powers label?

In 2021 the docket shows Texas v. Biden as a prominent example where state counsel — listed as William Thomas Thompson, Patrick K. Sweeten, and Ryan Daniel Walters — prosecuted a suit against the federal executive branch with claims implicating separation‑of‑powers principles. The available record identifies the case filing in 2021 and the named state attorneys, but the provided material does not detail all legal theories or the full roster of private firms that may have assisted. The Texas suit typifies state‑led litigation that presses separation‑of‑powers concerns by challenging executive policy choices or authority, and that tactic relies on state attorneys rather than the private‑firm structure seen in Seila ^[3].

3. Where do amicus groups and advocacy firms fit into the 2020–2021 litigation landscape?

The New Civil Liberties Alliance (NCLA) is cited as filing amicus briefs in 2021 matters such as litigation over components of federal statutes, indicating that advocacy organizations contributed litigation support and legal argumentation even when they were not plaintiff counsel. NCLA’s participation underscores how public‑interest litigators sought to shape separation‑of‑powers doctrine through briefs rather than originating suits, and it highlights a tactical split: private firms and state counsel typically bring the suits while ideational groups craft doctrinal arguments and public messaging to influence courts ^[4]. This division of labor affects both case selection and the legal framing advanced to judges.

4. How do the sources align or diverge about who led these challenges?

The Seila Law materials consistently attribute lead petitioner advocacy to Kannon K. Shanmugam and list Paul, Weiss among firms involved, with the Solicitor General representing the government’s side in 2020; those points are duplicated across both Seila summaries ^{[1] [2]}. The Texas v. Biden record separately names state attorneys for the 2021 filing, and does not indicate the same private‑firm leads as Seila, demonstrating a clear bifurcation between private‑firm petitioner litigation (Seila) and state‑led suits (Texas v. Biden). One source that catalogs law‑firm activity in 2025 is out of scope for 2020–2021 and should not be conflated with the earlier period’s roster ^{[5] [3]}.

5. What important context and omissions should readers know about these accounts?

The documents capture headline counsel but omit full litigation teams, co‑counsel lists, and the finer contours of legal strategy; for example, Seila involved multiple amici and supporting counsel beyond the named leads, and Texas‑era suits may have engaged outside counsel not recorded in the provided excerpt. The 2025 firm activity cited in one summary can create misleading impressions if read as contemporaneous with 2020–2021, so it is important to separate actions by date. The available materials also do not provide exhaustive lists of all separation‑of‑powers suits in those years, so while the named attorneys were central in high‑profile cases, other lawyers and firms likely led additional, less publicized challenges during 2020–2021 ^{[1] [2] [3] [4] [5]}.