Who decides what a regulation is?

The Fight Over California’s Vehicle Emissions Waivers and the Congressional Review Act

A recent New York Times article highlighted a brewing battle in Congress over the Environmental Protection Agency’s (EPA) waivers that allow California to set stricter vehicle emissions standards. While the public debate focuses on climate policy, the real procedural story is about the use of the Congressional Review Act (CRA) to challenge agency actions — and whether EPA waivers count as “rules” under the CRA.

The core question in this fight is who decides whether the CRA can be used for a particular executive branch action. The answer: Congress decides—and ultimately, this is a political question, not a legal one.

Before we jump into all that, let’s quickly review the process around the CRA.

CRA background and process

The CRA, enacted in 1996, gives Congress a powerful tool to review and potentially nullify federal agency rules within 60 legislative days. If a joint resolution of disapproval passes both chambers and is signed by the President (or survives a veto), the rule is voided, and the agency is barred from issuing a “substantially similar” rule without new legislative authority.

The typical uses of the CRA have been to terminate rules that were promulgated at the end of a president’s term. So most of the CRA resolutions that are being passed right now are Biden-era regulations that were finalized in the closing days of the Biden administration.

But the California waiver is not that typical case. This action is taking a waiver, something that has been traditionally understood by the Government Accountability Office as less than a rule, and reissuing it as a rule during the Trump administration. By reissuing it as a rule, the EPA made it eligible for CRA review. Not only would it end this particular waiver, but the “substantially similar” provision of the CRA would mean that a future regulation could not be issued by a future (presumably Democrat) administration.

This is definitely an aggressive and novel use of the CRA.

A key element of the CRA is that it uses “expedited procedures” to bring a vote to the floor, bypassing the normal processes. In both chambers, this allows an individual member to bypass leadership. In the Senate, this also means that the vote to disapprove the regulation is not subject to the filibuster.

What Is a Regulation, and Who Decides?

The heart of the current battle is whether California’s EPA waivers are “rules” under the CRA. This question has drawn sharp divisions across branches of government and between legal and political actors. While this can be framed as a legal question, the reality is that this is a political question.

EPA’s Position

In February 2025, the Trump EPA transmitted the waivers for California’s Advanced Clean Cars II, Advanced Clean Trucks, and Omnibus NOx rules to Congress, signaling that it views the waivers as subject to CRA review. This marked a notable expansion of the CRA’s application.

GAO’s Determination

Under the CRA, the Government Accountability Office issues a notice that a given executive branch action is subject to the CRA. GAO issued opinions in November 2023 and March 2025 stating that these waivers are not “rules” under the CRA but rather adjudicatory orders, exempt from CRA review.

GAO argued that even if the waivers met the APA’s definition of a rule, they would likely be classified as “rules of particular applicability,” which are excluded from CRA procedures.

GAO’s finding follows its precedent. I would prefer it remain consistent unless or until Congress provides new guidance—which may be happening now

House of Representatives’ Action

In April 2025, the House passed a CRA disapproval resolution on the waiver with a vote of 246-164, including 35 Democratic votes. This bipartisan vote indicates political support for the idea that the waivers function as rules with wide economic impact.

Senate Parliamentarian’s Guidance

The Senate Parliamentarian, Elizabeth MacDonough, concurred with GAO’s view, advising in April 2025 that the waivers are not subject to the CRA. Despite this, some Senate Republicans are pushing forward with efforts to trigger a CRA vote, illustrating the tension between advisory opinions and Senate political will.

Who Ultimately Decides?

Legally, the CRA relies on the Administrative Procedure Act’s definition of a rule. However, whether and how either chamber of Congress applies the CRA is a political decision informed but not determined by the recommendation of GAO and the parliamentarian. GAO and the Parliamentarian advise Congress, but they do not decide. Ultimately, elected members determine what Congress does. Article 1, Section 5 of the Constitution says that “Each House may determine the Rules of its Proceedings.”

While GAO issues opinions and the Parliamentarian advises, neither has binding authority. The only role of the Senate Parliamentarian is to advise the presiding officer about what the precedents of the Senate are. The presiding officer is not required to take the advice of the Parliamentarian.

In practice, the presiding officer rules on procedural questions, but any Senator can appeal—and the full Senate can override that ruling by majority vote. So what could happen, regardless of the recommendation of the GAO or the Parliamentarian, is that the presiding officer could determine the motion to act on the CRA resolution is in order. Alternatively, the presiding officer decides the other way. In either case, any Senator could move to overturn the decision of the presiding officer, creating a new precedent of the Senate.

This gives the full Senate, not the Parliamentarian, the final say on whether to treat the waivers as CRA-reviewable regulations.

Given the House’s vote, the EPA’s action, and the White House’s likely support, that would also reset the debate about the CRA and the lead to litigation

Next steps: GAO and the courts

There are several important next steps that would follow from this action in both GAO and the courts.

The first question is how GAO understands its role after this. Does it change its precedent to recognize the House and Senate action? My instinct is that it should, but I don’t have a clear sense that this question has ever been faced like this. This could be a defining moment for how GAO understands its role – and how Congress understands GAO’s role.

The second question is litigation. If the Senate passes the resolution of disapproval and the President signs it, California is likely to sue to protect its waiver. But there are significant legal hurdles.

The first hurdle is the CRA’s judicial review provision, 5 U.S.C. § 805, which states, “No determination, finding, action, or omission under this chapter shall be subject to judicial review.”

This generally means courts will not second-guess whether Congress validly passed a CRA resolution. However, courts may still hear challenges related to the underlying agency action, such as whether the agency properly classified or submitted the rule under the CRA. This gray zone adds complexity to the California waiver fight.

The second hurdle comes from INS v. Chadha (1983), where the Supreme Court invalidated the legislative veto precisely because it bypassed bicameralism and presentment. By contrast, CRA resolutions go through both chambers and require presidential signature, which gives them a high level of constitutional protection from separation-of-powers challenges above and beyond the bar on judicial review.

If this scenario unfolds, expect further legal and political developments. For now, we await the Senate’s next move.