K-Monitor Public Benefit Association has submitted an amicus curiae ("friend of the court") brief to the Constitutional Court in a case whose outcome may significantly affect the transparency of domestic political advertising. In our submission, we argue that the application of the EU regulation on the transparency of political advertising does not violate the Hungarian Fundamental Law; on the contrary, disregarding it would create serious legal uncertainty and endanger the transparency of democratic elections.

Background of the Case
From October 2025, Regulation (EU) 2024/900 of the European Parliament and of the Council on the transparency of political advertising became directly applicable in Hungary. The purpose of the EU legislation can be stated simply: anyone advertising political content must disclose who paid for the advertisement, how much it cost, and who the target audience is. The regulation therefore primarily aims to strengthen the transparency of online political advertising, with particular attention to targeted political communication on social media platforms.
In February 2026, the Commissioner for Fundamental Rights initiated a request to the Constitutional Court for an interpretation of the Fundamental Law on the grounds that the conceptual framework of the EU regulation—in particular its broad definition of political advertising—is not consistent with Hungarian media law and electoral law and that this creates legal uncertainty, and therefore the application of the regulation should be disregarded in Hungary. A few days later, Fidesz – Hungarian Civic Alliance, and subsequently the Prime Minister's Office, also submitted amicus curiae briefs supporting the Ombudsman's position.
What Does K-Monitor Argue and Why?
K-Monitor, as a civil organisation committed to transparency and the democratic oversight of the exercise of power, considers it important to join these proceedings in defence of the transparency of political advertising. We have taken a position in favour of applying the EU regulation on four main grounds.
1. Applying EU law is a constitutional obligation
Article E) of the Fundamental Law expressly provides that Hungary, as a Member State of the European Union, may exercise certain competences jointly with other Member States through EU institutions. Directly applicable EU regulations—such as the political advertising regulation—are mandatorily applicable in Hungary on the basis of the authorisation of the Fundamental Law.
The Constitutional Court has also established in its own consistent practice that the primacy of EU law can only be overridden in truly exceptional cases — when an EU norm violates the essential content of fundamental rights protected by the Fundamental Law, when it affects inalienable elements of sovereignty, or when it conflicts with constitutional identity. However, these limits are tools that can only be invoked in exceptional, last-resort circumstances.
In K-Monitor's view, none of these conditions are met in the present case.
2. "Political advertising" is not a closed, autonomous constitutional concept
The motion suggests that the term "political advertising" in Article IX(3) of the Fundamental Law is a timeless concept, definable solely by Hungarian law, from which the EU legislator cannot deviate.
However, the very text of the Fundamental Law indicates that the content of this concept is filled in by a Cardinal Act—meaning it is not an autonomous, closed constitutional category but a framework concept that requires legislative specification. The EU legislator is equally entitled to define such framework concepts for different purposes and in different contexts.
The concept of political advertising under Hungarian law is primarily tied to the campaign period and to television and radio broadcasting, with its main rules being free-of-charge provision and equal opportunities for candidates. The EU regulation, by contrast, focuses on the online and digital sphere of political communication, is not limited to campaign periods, and establishes transparency requirements: who is advertising, for how much, and to whom.
The two regulations do not address the same phenomenon—one concerns analogue broadcasting during campaign periods, the other concerns the world of digital political advertising. Therefore, any conceptual discrepancy does not represent a constitutional conflict, but rather a difference that can be resolved through interpretation.
3. It is precisely the application of the regulation that guarantees legal certainty
One of the arguments in the motion was that the joint application of two different conceptual frameworks creates legal uncertainty, violating the rule of law as enshrined in the Fundamental Law.
K-Monitor argues the opposite: it is the non-application of the regulation that would create legal uncertainty. The EU regulation was adopted in March 2024 and was made available to all stakeholders. Every affected party was aware that the EU regulation would become directly applicable in Hungary from October 2025, and media service providers, online platforms, and party press officers have adjusted their practices accordingly.
Moreover, the Constitutional Court itself has emphasised in its own practice that the stability of electoral rules is a particularly important value. It is therefore especially concerning that, during the electoral campaign period, the application of an EU regulation known to all affected parties is suddenly called into question.
4. Fundamental rights, sovereignty, and identity review are not applicable
The motion refers to three special control mechanisms developed by the Constitutional Court: fundamental rights review, sovereignty review, and identity review. These are tools by which the Court may, in exceptional cases, refuse the application of an EU norm in Hungary.
In K-Monitor's view, however, none of these are applicable here.
Fundamental rights review would only be warranted if the EU regulation violated the essential content of a fundamental right. However, a regulation requiring transparency in political advertising actually strengthens freedom of expression and the right to information. Those who know who is paying for a political message and how much are better equipped to make informed decisions.
Sovereignty review is applicable when an EU norm regulates an area of exclusive national competence. The electoral system is such an area; however, the legal basis for adopting the contested regulation was the EU's internal market and competition law competence. The transparency of the financing of political advertising is an internal market issue, not an electoral one.
Identity review can be applied when there is an infringement of fundamental and inalienable values related to the Fundamental Law and the historical constitution. Neither the concept of political advertising nor the transparency rules for online advertising fall within this category.
What Would Be the Constitutional Solution?
We argue that the correct constitutional response is not to disregard the application of the regulation but to declare that Hungarian authorities—regulatory bodies, courts, and the media authority—are obliged to interpret domestic media law and electoral law in conformity with the EU regulation.
This is the principle of EU-conform interpretation, which has been elaborated on multiple occasions by both the Court of Justice of the European Union and the Constitutional Court. Its essence is that if there is tension between national law and EU law, this must be resolved primarily through an interpretation that seeks coherence.
In K-Monitor's view, interpretation is entirely sufficient in the present case since Hungarian rules on political advertising can be interpreted in a way that avoids conflict with the transparency obligations of the EU regulation—as the two frameworks target different areas.
Why Does This Motion and the Related Decision Matter?
For K-Monitor, this case is not an abstract question of constitutional law. The transparency of political advertising is one of the most important guarantees of democratic elections. If voters do not know who is paying for a political message and how much, they cannot make truly informed decisions.
The EU regulation addresses precisely this problem: it compels those who commission or disseminate political advertisements to make mandatory disclosures. This is especially important in the age of targeted online political advertising, when different groups of voters may receive entirely different messages without being aware of it— or without the public being aware of it.
The case before the Constitutional Court may therefore determine whether the EU-level transparency standard for political advertising is enforced in Hungary or whether Hungary disregards the application of a directly applicable EU regulation adopted within the framework of jointly exercised competences. K-Monitor believes that a decision is needed that simultaneously respects the primacy of EU law, the requirement of legal certainty, and the transparency of democratic elections.
K-Monitor's submission in Hungarian is avaialble here.





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