The Warsaw Convention and the Hague Protocol are both related to the responsibility of international carriage by air. Is the relationship between the two successive in nature or amendatory? If one of the two is a successive treaty relating to the same subject matter, then the Article 30 of the Vienna Convention on the Law of Treaties(VCLT) could provide an applicable solution, whereas a view regarding it as an amendment of the previous convention will have to find an applicable provision for the matter at Article 40(5)(b) of the VCLT.
The relationship between the Warsaw Convention and the Hague Protocol becomes an issue when the states concerned are not parties to both, -to wit, when State A is only a party to the Warsaw Convention and State B only to the Hague Protocol. There are four different views about their relations.
The first view argues that although these two conventions are separate instruments, the provisions that are not amended continue to apply, therefore leaving something to apply to both parties. The United States District Court for the Southern District of New York and The Korea Seoul Civil Court have taken this view, leaving a result of applying provisions that none of the case parties have consented on.
The second view is of the opinion of the Supreme Court and the High Court of Korea. The Supreme Court of Korea, while applying the Hague protocol to the case, adopted the view that “the Hague Protocol is not a denunciation of Warsaw Convention making a new treaty. The Hague Protocol is a mere amendment of the Warsaw Convention.”
The third view applies the Warsaw Convention because it understands the Hague Protocol as an amendment of the Warsaw Convention. Based on the presumption given by the Article 40(5)(b) of the VCLT, any State which becomes a party to a treaty after the entry into force of its amending agreement, automatically becomes a party to the original convention as well. But, as Frankowska properly pointed out, Paragraph 5 of Article 40 of the VCLT contemplates a situation where the State becomes a party to the original treaty after its amending agreement has already entered into force. When this situation occurs, the original treaty is the choice of law between States with the original treaty. Additionally, both treaties could apply when one State is a party to the original and the amended conventions as well. However, the case before the court is materially different because the State becomes a party to the amended convention only. Also, as Gardinar has noticed, Article 18 of the Hague Protocol clearly writes down the scope of the Protocol as “the place of departure and destination referred to in that Article are situated either in the territories of two parties to ‘this Protocol’...” Finally, Articles 21(2) and 23(2) of the Hague Protocol provide that the adherence to the Protocol be a party to the Convention ‘as amended by the Protocol’.
The fourth view is of the opinion that the two conventions are separate instruments and that no applicable convention is available for the two parties when they respectively ratified different conventions. Articles 19 and 24(3) of the Protocol both support the interpretation of the Convention and the Protocol as one single instrument between the Parties to ‘this Protocol’. Despite appearances, the Protocol does not simply introduce amendments to the original treaty.