The second avenue of attack against the British (and by extension the United States) possession of the Chagos has come from Mauritius. As in the author’s September 2017 legal assessment, Mauritius pursued an action in 2015 in an UNCLOS international arbitral tribunal to set aside the UK’s declaration of large areas of the Chagos Archipelago to be Marine Protected Area (MPA). Mauritius’ contention was that UK’s MPA detachment of the BIOT from the Dependency of Mauritius gave Mauritius fishing rights in the waters of Chagos and that the MPA could not encroach on those rights. At the time the BIOT was detached from Mauritius, the transfer documents (Lancaster House Undertakings) promised Mauritius some form of preferential” treatment to resources of the Chagos for fishing and other purposes. Given that the UK had repeatedly ratified the Lancaster House Undertakings through its actions, the Tribunal unanimously ruled in Mauritius’ favor that the UK could not unilaterally restrict Mauritius’ fisheries rights by establishing a MPA without prior consultation.

UN General Assembly (UNGA) Asks World Court to Assess theBIOT

The most recent, and perhaps most significant, litigation development has to do with an action that was initiated in June 2017 by the UNGA seeking advisory opinion from the International Court of Justice (ICJ) as to validity the 1965 detachment of the BIOT from the rest of the Colonial Mauritius. Had the Chagos remained part of Mauritius, then DGAR would have been assimilated into Mauritius when it became independent in 1968. Attacking the transfer at the point of inception today obviously create legal doubt as to who is the true owner of the Chagos Archipelago and, by extension, Diego Garcia.

On the merits, there are facets of this case which the UK will have difficulty overcoming. The 1965 detachment of Chagos Archipelago was codified in a provisional understanding between the British Secretary of State and the Premier of Colonial Mauritius in the above noted series of documents known as the Lancaster House Understandings. It was there agreed that the UK would detach the Chagos and would pay £3 million in compensation to Mauritius above and beyond resettlement costs. The UK is also expected to pay the resettlement costs of the former residents.

- Use its good offices with the United States to support Mauritius’ request to use labor and materials from Mauritius for construction work on the islands:

- Return the islands if the need for the facilities on the island disappeared (defense purposes) (documented in a later exchange of letters);

- Accrete oil or mineral rights to Mauritius; and

- Use its good offices with the U.S. government to ensure that the following facilities in the Chagos would remain available to Mauritius as far as practicable: (a) navigational and meteorological facilities; (b) fishing rights; and (c) use of runways for emergency landing for refueling planes.

- When Mauritius became independent in 1968, the Mauritian Council of Ministers ratified that Landcaster understandings although the UN General Assembly objected to the detachment of the Chagos on three separate occasions.

The UK’s basic contention is that it has complied with all aspects of the promises that it made to the Mauritian colonial administration in 1965 in the Landcaster Understandings. It paid Mauritius £3 million and it continues to promise to cede the islands back to Mauritius when “no longer needed for defence purposes.” The UK will assert that it paid all of the sums due to Mauritius, and to the former residents, and assert that the Chagos, DGAR in particular, is an essential defense installation.

Mauritius will argue that the Chagos Islands are an integral part of Mauritius and could not be disassembled and should remain with Mauritius; then and now. They will assert so-called 1965 Lancaster House Undertakings with the UK was "obtained under conditions of duress and coercion" and did not represent an agreement among two sovereign countries i.e., it was an agreement between one component of the British government and another. The Mauritians may also argue that “defense purposes” language was designed to benefit the UK and not the United States.

Questions Presented

This case involves a request from the UN General Assembly (UNGA) for the ICJ to issue an Advisory Opinion. The matter was initiated by Mauritius in June 2017 and passed by a vote of ninety-four in favor, sixty-five abstentions, and fifteen opposed. India voted in favor of the resolution. Recalling again that the UNGA had three times asked the UK to not “dismember” the Chagos from ahead of its independence, in 1968, the UNGA requested that the ICJ issues an advisory opinion on two questions:

First, “was the process of decolonization of Mauritius lawfully completed when Mauritius was granted independence in 1968, following the separation of the Chagos Archipelago from Mauritius” and having regard to international law?

Second, what are the consequences under international law arising from the continued administration by the United Kingdom . . . including with respect to the inability of Mauritius “to implement a programme for the resettlement on the Chagos Archipelago of its nationals, in particular those of Chagossian origin?”

The power of the ICJ to render advisory opinions to organs of the UN has been recognized under Article 65(1) of the ICJ Statue, which provides that the Court “may give an advisory opinion on any legal question at the request of whatever body may be authorized ...” to include the UN General Assembly. Advisory opinions are not designed to settle disputes between states (since they must both generally consent) but, here, can provide definitive legal advice to organs of the United Nations. The UK will argue that Mauritius and the UK are the real parties to this dispute and the involvement of the General Assembly circumvents the requirement that there be consent between the two affected states. The fact that the UK had been chastised three times by the UNGA for its detachment of the BIOT in the 1960s and was admonished by the UNCLOS Tribunal for its shabby treatment of Mauritius in relation to the MPA designation vis-à-vis Mauritius, it is hard to envision that the ICJ will dismiss given that the UNGA, and the UN generally is suppose to advocate on behalf of those from non-self-governing territories.

The next question for U.S. and UK policymakers is whether an adverse “advisory” opinion makes any practical difference since it is not binding on states. But UN Agencies do have an obligation to follow the advice of the International Court of Justice. Therefore, if the ICJ directed that the UNGA takes certain actions (under Article 73) relative to current and former residents of non-self governing territories, the UNGA has considerable discretion to ensure that the rights of the Chagossians are protected e.g., order some trusteeship arrangements. This would be politically messy for both the United States and UK; especially since purpose of such a ruling is to remedy the ill effects of colonization.

At least one legal scholar argues that even though Mauritius petitioned to have the UNGA to bring this action that the UNGA is the real party in interest since its orders were ignored three times (1965–1967) the case involves bigger question whether important norms of self-determination were violated by the UK, Mauritius and, perhaps the UNGA for failing to take action to protect the rights of the former Chagos residents. The scholar suggests, for example, the “defense purposes” rationale for continuing to keep the residents of DGAR was not made in good faith by the UK because various UN requirements (See, e.g., Art 73(3) of the UN Charter) to keep UN offices informed that a security requirement prevented the return of the former residents. Lastly, this same scholar suggests the Landcaster House Understanding lacked standing to trump the self-determination rights of the dispossessed individuals or eliminate the continuing obligations of the UK and Mauritius protect the former Chagos residents.

Article 73 of the UN Charter puts people from non-self-governing territories on a legal pedestal and it is curious that the UNGA is taking up the cause at such a late date since it is doubtful that many of their descendants would, ever want to live on DGAR in the middle of the Indian Ocean. However, that is besides the point since the UNGA seems determined to make a strong legal and political point with the UK and, perhaps the United States.

India is the Key

India has exercised leadership in the UN in the G-77 among developing countries and has substantial ethic and economic ties to Mauritius. India supported the UNGA resolution to refer the Chagos matter to the ICJ. This overall matter prompted a spirited debate within India which, on the one hand wanted to support the decolonization process but on the other had did not want to upset the current security balance in the Indian Ocean or force the United States off of Diego Garcia. This deference to not upsetting the U.S. presence in the Indian Ocean does, by the way, represent a change in Indian thinking because it had previously opposed all foreign ships in the Indian Ocean or port visits to DGAR.