The European Union is undergoing a fundamental transformation in the way it makes law. Responding to calls for simplification and competitiveness, echoed and amplified by demands of the US Administration, the Commission has embraced omnibus legislation – single acts that amend multiple legal instruments across disparate regulatory domains – as the principal mechanism for systematic deregulatory reform. Once limited to technical consolidation, the omnibus has become a vehicle for substantive policy change.

Since January 2025, the Commission has proposed six omnibus packages spanning sustainability, investment, agriculture, single market rules, defense, and chemicals. More than half of its 2026 proposals are packaged as omnibuses, covering areas as diverse as digital regulation, environmental policy, food and feed safety, automotive standards, energy products, taxation, and citizenship.

This shift, exemplified by the 2025 Omnibus I Simplification Directive (which amends the Corporate Sustainability Reporting Directive and Corporate Sustainability Due Diligence Directive), fundamentally alters the procedural architecture through which regulatory change occurs.  It introduces legal vulnerability and policy uncertainty: precisely the outcomes the Simplification agenda was meant to avoid. Used systematically and without constraint, a generalised use of the omnibus risks transforming this legislative technique into a tool of constitutional drift, a means of achieving through procedural shortcuts what could not be attained, at least not with the same speed and form, through ordinary policymaking. To remain legitimate within the EU’s legislative toolkit, omnibus lawmaking demands constitutional discipline.

From technical tool to constitutional drift

Bundled legislation has long carried a whiff of illegitimacy. The Romans called it lex satura and banned it in 98 BC under the lex Caecilia Didia for mixing unrelated provisions. The EU has occasionally used omnibus techniques to tidy up existing law – for instance, consolidating consumer protection rules or aligning non-legislative procedures after the Lisbon Treaty – but those efforts were limited and focused on genuine administrative simplification.

Under the Better Regulation Toolbox and REFIT programme, simplification was conceived as an administrative exercise: preserving the nature and purpose of obligations while improving coherence and eliminating redundancy. The 2025 omnibus wave departs radically from this approach. These new omnibuses are not tidying exercises but vehicles for substantive policy revision. They raise thresholds, dilute obligations, postpone enforcement, and repeal existing norms in the name of competitiveness. More critically, they roll back regulatory commitments without the level of stakeholder engagement and evidentiary support required by the Treaties, while also negatively affecting Charter-protected rights (as argued here).

The procedural shortcuts of omnibus lawmaking

Bundling legislative amendments into a single act can have serious procedural consequences. Omnibus proposals typically bypass safeguards built into the ordinary legislative process, including public consultations mandated by Article 11(3) TEU, impact assessments, inter-service consultations prescribed by the Commission’s Better Regulation Toolbox, and the Inter-Institutional Agreement on Better Law-Making.

None of the 2025 omnibus proposals underwent proper impact assessment or full public consultation. The Commission chose not to conduct an Impact Assessment for Omnibus I, invoking a “derogation” under its Better Regulation Guidelines and citing two justifications: (1) the importance and urgency of competitiveness concerns and (2) the existence of comprehensive impact assessments for the original legislation being amended. Yet these justifications apply to virtually all omnibus initiatives, meaning the Commission has created a standing exemption from its own evidentiary and consultative duties.

This conflicts with established case law according to which the decision not to carry out an Impact Assessment must be justified by a “particular situation,” to be proven and examined on a case-by-case basis (Judgment of 3 December 2019, Czech Republic v Parliament, para 85). By defining “competitiveness” as an urgent justification, the Commission has turned a political preference into a procedural exception. Tight political timelines – such as the four-month drafting window imposed by the 2025 Competitiveness Compass agenda – cannot amount to such an exceptional situation.

The result is a pattern: omnibus legislation functions as a procedural bypass. It allows the Commission to move fast, but at the cost of transparency, evidence, and participation. The more it becomes the default legislative technique – that is what is happening –, the more the EU’s procedural integrity is hollowed out.

The proceduralization of proportionality review

The absence of an impact assessment by the EU Commission – or that of a supplementary impact assessment by the EU legislature on its own amendments – does not automatically invalidate EU legislation. Yet under the Court of Justice’s evolving jurisprudence, it may amount to a breach of the principle of proportionality enshrined in Article 5(4) TEU and Protocol (No 2) on the application of the principles of subsidiarity and proportionality (Article 5). This conclusion follows from the Court’s evolving jurisprudence proceduralizing proportionality review.

In its Mobility judgment, the Court established that proportionality review requires EU institutions to demonstrate they “actually exercised their discretion” based on “detailed and solid material.” According to this standard, a breach of proportionality occurs when the EU legislature “does not have sufficient information enabling it to assess the proportionality of an adopted measure”, that is, to exercise its discretion “effectively on the basis of all the relevant elements and circumstances of the situation which the act adopted is intended to govern”.

This reasoning has profound implications for omnibus legislation. By eliminating impact assessments, the Commission deprives both itself and the co-legislators of the factual foundation required for reasoned proportionality review.

Omnibus I: exemplifying the constitutional drift

The Omnibus I Simplification Directive exemplifies this evidentiary failure. For example, the proposal to raise CSRD thresholds and exclude listed SMEs lacks a comparative analysis of whether ongoing European Sustainability Reporting Standards (ESRS) reforms could deliver equivalent relief without reducing reporting scope. Similarly, the limitation of CSDDD obligations to “tier 1” suppliers, presented as a simplification, does not appear to have considered risk-based models or technical support to facilitate compliance.

Moreover, by conducting closed consultations with select industry representatives while excluding broader stakeholder participation (rebranded as “Reality Checks”), the process violates the deliberative quality that legitimizes the exercise of legislative discretion. The principle of participatory democracy enshrined in Article 11 TEU becomes hollow when “consultation” means access for regulated industries but exclusion for affected communities, workers, and civil society organizations.

This suggests that, while any Omnibus legislation could theoretically undergo a full impact assessment and consultation, the Commission and EU legislature use the omnibus legislative technique as a vehicle to avoid these requirements. Yet the Commission could easily have (i) conducted comprehensive impact assessments for each legislative measure being amended; (ii) run proper 12-week public consultations; and (iii) provided draft texts for stakeholder review. Instead, the choice of the omnibus format allowed it to avoid these requirements in the name of urgency.

The Omnibus technique is not per se illegal under EU law

As a legislative technique, the Omnibus is not inherently incompatible with EU law. The EU’s historical use of omnibus instruments in limited contexts, such as sectoral updates, demonstrates that the technique can serve legitimate purposes of legislative efficiency and regulatory coherence when properly constrained by constitutional safeguards. However, when omnibus legislation is employed to systematically avoid impact assessments, bypass consultation periods, and skip the evidentiary requirements increasingly required to satisfy the principle of proportionality, it ceases to be a neutral procedural tool and becomes instead a mechanism for constitutional drift, a means of achieving through procedural shortcuts what could not be attained, at least not with the same speed and form, through ordinary policymaking.

A dedicated regime for omnibus legislation

The systematic constitutional deficiencies identified above are not inevitable features of omnibus legislation but rather consequences of its deployment without adequate procedural constraints. If omnibus legislation is to occupy a legitimate place in the EU’s legislative toolkit, it requires constitutional discipline analogous to existing safeguards governing other bundling mechanisms.

To legitimate the omnibus technique, the EU should codify procedural safeguards akin to those governing delegated act bundling under the Inter-Institutional Agreement on Better Law-Making (para 31). This provision embodies three critical principles: (1) bundling requires objective justification, not the mere invocation of urgency or administrative convenience; (2) justification must demonstrate substantive linkage between consolidated provisions; and (3) bundling remains subject to specific constraints that the legislative act may impose.

As it was suggested to me by Merijn Chamon, these principles, developed to prevent arbitrary consolidation of delegated acts, apply with even greater force to omnibus legislation affecting secondary law. Ultimately, if the EU requires substantive justification for bundling non-legislative measures, constitutional logic demands heightened requirements for bundling legislative amendments that substantively alter regulatory obligations, affect fundamental rights, and reshape the balance between regulatory protection and economic freedom.

These requirements could be implemented through revision of the Inter-Institutional Agreement on Better Law-Making, adding provisions specifically addressing omnibus legislation that parallel existing constraints on delegated act bundling. Alternatively, the Court of Justice could develop them through proportionality jurisprudence. Where institutions cannot demonstrate substantive linkage, fail to conduct adequate assessment, or proceed without considering alternatives, the absence of an evidentiary foundation necessary to satisfy proportionality review must prevent them from relying on the omnibus format.

The need for procedural discipline in omnibus legislation arises from the EU’s constitutional identity as a Community based on the rule of law (Les Verts, Case 294/83). As a new case pending before the Court reminds us (Case T-563/25, Green Impact ETS on wolves), legislative efficiency cannot justify procedural shortcuts when the Union’s legitimacy depends on the reviewability and accountability of its acts. Even its most ambitious and urgent simplification agendas must unfold within, never outside, the discipline of law.

Conclusions

As additional Omnibus proposals have been announced, a fundamental question confronts the EU institutions and its member states: Does the systematic procedural evasion documented here represent an isolated deviation subject to correction, or does it inaugurate a new constitutional normal characterized by constitutional drift?

The choice is not merely technical. It defines what kind of constitutional order the Union will leave to future generations: one where political priorities and efficiency considerations are bounded by legality, or one where legality yields to the politics of haste. This is all the more important because, as Omnibus I illustrates, this systematic regulatory roll-back may directly affect the protection of fundamental rights. While the Charter of Fundamental Rights does not forbid the EU legislature from lowering a previously chosen level of fundamental-rights protection, the Court’s case law has consistently viewed any sudden step-back with particular suspicion.

The EU Parliament’s mini-plenary vote on the Omnibus I scheduled for November 13 offers a ‘test case’ not only on the political viability of the use of this legislative technique, but also on the legal resilience of the European Union’s constitutional integrity.