After diplomatic pressure from Spain and the European Union, Repsol will still have a long way to go in its litigation against Argentina. On the one hand, it could sue the Argentine State before the Argentine courts, appealing the expropriation, the compensation it may receive, or both. This route is unlikely, because such a lawsuit would be heard under Argentine law and there is little chance that, under Argentine law, the rule expropriating YPF would be illegal or unconstitutional, because it is the Argentine State itself that approves it. Repsol can probably also appeal the amount of the compensation that Argentina decides to grant it, although with the same danger that this resource could be interpreted as a Withdrawal to a future international procedure . The oil company could also ask Spain to sue Argentina before an international court, but Spain, as a signatory of the 1965 Washington agreement , has almost totally renounced to such possibility. Repsol is left with arbitration, as provided for in the 1991 Spain-Argentina Treaty for the protection of investments.

The same Spain-Argentina Treaty contains the rights that protect Repsol, as an investor, at the international level; that is to say, the arbitral tribunal to be formed will have to ascertain whether Argentina has violated such rights, while also applying Argentine law. In this sense, the Treaty provides that Argentina may nationalize assets located in its territory (and YPF's shares are), but it will have to do so in the public interest, in accordance with the legal provisions of Argentine law and without being discriminatory. In addition, an adequate compensation in convertible currency will have to be paid. The amount of this compensation will probably be the crux of the matter in the litigation, since the right to expropriation itself is hardly contestable. In the international internship , "adequate" compensation usually means the full value of what is expropriated, but the concept may vary from treaty to treaty, and the Spain-Argentina case is quite brief on this point.