Regarding the conclusion concerning the concealment of sanctions for a trade regulation (the first point of the Hungarian lawsuit), it should be noted that the sanctions regime is not based on anything (not even the text of the regulation itself) other than the claims of politicians. From a legal point of view, it is highly unlikely that the court will consider this as relevant facts.

In its argumentation on the second point, the Slovak Republic stated that, as a landlocked country, Slovakia does not have direct access to LNG terminals. Despite significant investments in interconnections and infrastructure development, there are problematic areas outside the territory of the Slovak Republic that limit access to sufficient alternative gas supplies and their affordability.

There are therefore serious legal and financial risks arising from long-term gas supply contracts, including possible arbitration disputes and compensation claims. The Slovak Republic also had reservations about the legal basis chosen for the regulation and its compliance with the principles of proportionality and energy solidarity.

However, the latter reference to energy solidarity at the European Union level may represent a significant chance of success in the lawsuit, as the Court of Justice of the European Union has already ruled in favor of a member state in a similar case.

The dispute over energy competences

The lawsuit mentioned by the Prime Minister does not yet have a specific form, and therefore it is only possible to base one's opinion on what has been presented in public statements by government officials or the media.

In its lawsuit, the Slovak Republic may argue for energy independence and security of energy supply, which fall within the competence of the member state, as well as the economic and energy disadvantage that will undoubtedly arise after cutting off Russian sources.

However, the Treaty on the Functioning of the European Union stipulates that the Union shall, in a spirit of solidarity, address the functioning of the energy market, its security, and promote its interconnection (Article 194). Member States have competence over the use of their own energy resources, but the European energy market as a whole is managed at Union level.

The Union will argue before the court, with reference to the content of the regulation, that this is a matter of the cross-border market and security of supply. From the perspective of EU law, this is therefore a clear case of transcendence to the European level, which does not concern a single Member State exclusively.

The challenge of proving subsidiarity

The principle of subsidiarity is enshrined in the Treaty on European Union (Article 5(3)) and essentially means that the EU should only act if the objectives of the proposed measure cannot be satisfactorily achieved at Member State level and can be better achieved at Union level.

On the issue of subsidiarity, Slovakia would have to prove that the EU did not consider any alternatives, ignored the specific position of landlocked states, and only formally referred to subsidiarity without actually analyzing it.

However, it can already be said that, from the Union's point of view, there are extensive studies that analyze cutting off Russian sources as a necessity. The reason is the war in Ukraine and the possible use of Russian energy resources to finance the war or weaken Ukraine and its allies.

In this regard, the argument that Member States have the right to choose their energy sources or supply structure is unlikely to hold water, as the ban on Russian gas imports is seen as a measure to strengthen energy security and market resilience, as well as a trade measure to strengthen the European Union as a whole.

The EU will use similar arguments with regard to the principle of proportionality. However, in applying the principle of energy solidarity, which is enshrined in the Treaty on the Functioning of the European Union (Article 194), the Union has already encountered difficulties before the Court of Justice of the European Union in the past.

The Polish precedent

This was case T-883/16, in which Poland, supported by Latvia and the Republic of Lithuania, brought an action against the European Commission, supported by Germany. The subject of the dispute was the decision on the basis of which the Commission granted and subsequently amended an exemption for the OPAL gas pipeline from the rules that normally govern third-party access to transmission infrastructure and tariff rules within the internal gas market.

The Republic of Poland argued before the court that the contested decision violated the principle of energy security and the principle of energy solidarity, since the granting of a new exemption for the OPAL gas pipeline threatened the security of gas supplies in the Union, particularly in Central Europe.

The essence of Poland's argument was that there had been a reduction in gas transmission through the Yamal and Brotherhood pipelines, which could lead to a weakening of Poland's energy security and a significant disruption of the diversification of gas supply sources.

On this point, Poland had essentially similar objections to those presented today by Slovakia, namely in connection with the reduction in gas flow through its pipelines, which is damaging to it in energy and financial terms and leads to increased dependence on gas imports via other routes.

In this case, the Court of Justice of the EU recognized that the Commission had failed to adequately assess the impact on other Member States and on the single market in its decision, thereby violating the principles of solidarity and the proper functioning of the internal energy market.

The Court also annulled the contested Commission decision and concluded that decisions concerning energy infrastructure and the market must take into account the consequences not only for the market as a whole, but also for all Member States concerned. This set a precedent whereby common market rules and solidarity between states take precedence over the unilateral economic interests of a single country or a third party.

The outcome will hinge on the legal strategy

The Slovak Republic may refer to this judgment in its lawsuit, arguing that energy solidarity has been violated by failing to take into account the economic and energy interests of the country. Given the existence of a similar case and the decision of the Court of Justice of the European Union, a similar assessment can be expected in comparable circumstances.

Although it is possible to build a relevant legal argument on this case, the success of the lawsuit itself will depend on its conception and the way in which the legal issues are approached. In this case, the factual circumstances are different, at least in terms of how Member States and the European Union view the situation.

From the EU's point of view, the main concern is market security and stability, which are to be achieved by cutting off Russia as an aggressor. On the other hand, however, there is no guarantee that Slovakia's economic position in terms of gas supplies or its revenues from gas transit to other countries will be maintained.

The entire dispute and its significant economic consequences will rest on the shoulders of those who file a specific lawsuit and present their arguments before the Court of Justice of the EU.

However, it remains an indisputable fact that the argument of energy solidarity will be a strong card in favor of the Slovak Republic, which could be significantly damaged by being cut off from Russian gas supplies.