Noting that the court - which ruled Slovenia's case against Croatia over the latter's ignoring of the arbitration decision inadmissible - had proposed this step as part of its decision, Lenarčič said the two sides could confront the court with a very simple question: is the arbitration decision binding on both sides or not.

"The court invited both countries to look for a solution and mentioned Article 273 [of the Treaty on the Functioning of the EU], which entails them submitting the conflict to the same court in agreement," said Lenarčič, Slovenia's ambassador to the EU before becoming crisis management commissioner.

Asked whether Article 273, which gives the court jurisdiction in any dispute between member states "if the dispute is submitted to it under a special agreement between the parties", was a good option for Slovenia, Lenarčič said this had always been a good option.

"The problem is it requires the consent of both sides," he added, while arguing the court, albeit stating clearly enough it expected both sides to implement the arbitration decision, had decided to interpret its competences very narrowly in this case.

While Lenarčič personally believes the court could also decide on violations of EU law, he added that "it made the decision that it made, it is final and there is not much sense in discussing it".

Still, Lenarčič seems to agree with the view of Slovenian agent Maja Mernard, who said the court's decision was a dangerous precedent that was opening the door to violations of EU law.

He said that cases could indeed emerge where the court would not want to or be able to rule on instances of EU law violations merely because they stem from different legal fields, meaning international law.