Shortly after the establishment of the UN the legal personality of international organisations became the subject of the ICJ’s Reparation for Injuries case. In this case the ICJ considered that international personality is indispensable to enable UN to meet its purposes and principles as laid down in the UN Charter.²⁴ However, the Charter does not explicitly provide for the UN’s international personality. In the opinion of the ICJ it is nevertheless undeniable that the functions and rights allocated to UN can only be explained by the intention of its founding members to grant it a large measure of international personality.²⁵

The UN Charter contains several provisions, in which the UN’s capacity to conclude international agreements is laid down. For example, Article 43, subparagraph 1, enables UN to conclude agreements with States on the contribution of armed forces to crisis management operations and on related assistance and facilities.²⁶ With a view to the international personality of UN it can be assumed that Article 43 concerns treaties. The Charter remains tacit on the possibility to conclude international agreements with respect to other issues, such as SOFAs in the context of crisis management operations.

Whenever such a capacity has not explicitly been provided for, it may be implicit. In the Reparation for Injuries case the ICJ observed the following with regard to UN:

Under international law, the Organization must be deemed to have those powers which, though not expressly provided in the Charter, are conferred upon it by necessary implication as being essential to the performance of its duties.²⁷

One of UN’s main tasks is to promote international peace and security. To this end UN have established a number of crisis management operations. This activity implies the capacity to conclude agreements, such as SOFAs, with the States where the operations take place. UN’s broad practice in this field confirms the organisation’s authority to conclude international agreements. Furthermore, as mentioned in the preceding section, the UN possesses objective personality, which means that its personality applies to all States and international organisations.

The establishment of NATO is related to the 1949 NATO Treaty, although this agreement does not explicitly define NATO as an international organisation. As a consequence there are hardly any institutional provisions in the NATO Treaty. These provisions can be found in additional agreements, such as the Ottawa Agreement,²⁸ regulating the civilian institutions and the Paris Protocol,²⁹ defining NATO’s military headquarters.³⁰

Article I(a) of the Ottawa Agreement defines the ‘organisation’ NATO as consisting of the North Atlantic Council (NATO Council) and its subsidiary bodies. Article IV determines that NATO possesses both the juridical personality and the capacity “to conclude contracts, to acquire and dispose of movable and immovable property and to institute legal proceedings.” The nature of the enumerated capacities refers, however, to NATO’s legal personality under national law. Other provisions of the agreement imply that NATO has international personality as well. For example, the organisation enjoys immunities that are comparable to those of diplomatic missions and it has the capacity to conclude treaties (see discussion below).³¹ Considering these aspects, NATO’s legal advisor rightly remarked³²:

NATO, as an intergovernmental organization, is a subject of international law … entitled to rights, duties or powers established in international law, and, generally, the capacity to act on the international scene.³³

The international personality is necessary to achieve the organisation’s purpose, which is: “…the further development of peaceful and friendly international relations…”.³⁴ Therefore, the organisation has, inter alia, treaty-making powers. Article XXV of the Ottawa Agreement covers the NATO Council’s capacity to represent the organisation and to conclude complementary agreements in its name. The Council has used this capacity to conclude agreements on the status of the organisation’s bodies in member States.³⁵

In addition, Article XVI of the Paris Protocol enables NATO’s Supreme Headquarters³⁶ to conclude supplemental agreements with receiving States on the Protocol’s application.³⁷ The fact that NATO’s subordinate headquarters have these powers implies that the organisation itself also possesses such a capacity. In any case NATO’s tasks and functions with respect to international military cooperation require the capacity to conclude agreements regarding those tasks and functions. This line of reasoning is confirmed by NATO’s practice of concluding treaties with States and international organisations³⁸ on various topics related to military cooperation, such as status of forces.

NATO’s decision-making procedure deserves particular attention, because its member States retain almost all decision-making powers and are directly involved in the administration and operation of NATO.³⁹ Decisions are taken by consensus, which means that a decision is only adopted when all States accept it:

Decisions are thus the expression of the collective will of the Sovereign member States, arrived at by common consent and supported by all.⁴⁰

This decision-making process also applies to the Council’s decisions on NATO-led operations.

Whether NATO also possesses an objective international personality has not clearly been established yet. The current number of 28 NATO Member States constitutes a minority within today’s international community, which consists of more than 190 States. Therefore, the assertion that NATO possesses objective personality does not seem to be very convincing. Nevertheless, the organisation does not only fulfil an important regional task, but has also been influential in the field of international peace and security further afield.⁴¹ In this respect mention can be made of the UN authorization to take over its crisis management operations (IFOR/SFOR), or to execute major operations (ISAF, the anti-piracy operations near Somalia and the operations with respect to Libya in 2011). In the context of these operations, NATO has concluded international agreements with third States and international organisations, without its legal personality being disputed. Therefore, it seems plausible to conclude that NATO possesses objective international personality.

Today the position of the EU is well established. Initially, and similar to UN and NATO, an explicit conventional provision on its legal personality did not exist. In 1997 the Treaty of Amsterdam added Article 24 to the Treaty on European Union (hereafter TEU),⁴² enabling the EU to conclude treaties within the field of the common foreign and security policy. Since 2001 this legal basis has frequently been used by the EU Council, as a EU institution,⁴³ to conclude a number of SOFAs for EU crisis management operations,⁴⁴ which leads to the conclusion that the EU has legal personality.⁴⁵ Any remaining controversy on the issue was put to rest with the adoption of the Treaty of Lisbon,⁴⁶ which added Article 47 to the TEU stating: “The Union shall have legal personality.” Furthermore, a sentence was added to Article 1 of the TEU determining that the Union “shall replace and succeed the European Community (EC).” Article 281 of the EC Treaty saw to the legal personality of the EC,⁴⁷ although it did not specify whether it concerned personality under national or international law. However, due to the capacities attributed to the EC in the same treaty, it was generally accepted that it included international personality.⁴⁸ So, it is beyond doubt that the EU has acquired this status. From the discussion above on the objective international personality of NATO, it can be concluded that the same applies to the EU.

States establish international organisations that in their own name serve the agreed common interests of the participating member States. In this sense they embody the member States’ sovereign powers reflected in the purposes and functions of the organisations. Therefore, the international organisations will have to be able to function without the unilateral interference of member States, in particular of the State on whose territory the organisation is located.⁵² Essentially for this reason host States grant international organisations immunities necessary to guarantee the independent exercise of their functions (doctrine of functional necessity).⁵³ As the purposes and the functions of international organisations vary widely, so does the status of organisations and their staffs.

Treaties on the status of international organisations generally grant the organisations absolute immunity from jurisdiction⁵⁴ and as a result they do not distinguish between acta jure gestionis and acta jure imperii.⁵⁵ Furthermore, it is common to exclude certain forms of responsibility from immunity, such as damages arising from traffic accidents.⁵⁶ Likewise, in the field of commercial transactions the treaties often provide for arbitration as an alternative means to settle disputes⁵⁷ in order to ensure that parties entering into legal relations with the international organisations can take legal action, if necessary. Lastly, the international organisations may refrain from immunity altogether.

In the absence of a treaty most national courts will not accept immunity of an international organisation.⁵⁸ An exception is a Dutch Supreme Court’s case, in which it was considered that under international customary law an international organisation is entitled to immunity of jurisdiction in the State where it has its seat with the consent of the host State.⁵⁹

The special position of international organisations requires that both organisations and their staffs can execute their functions independently from the host State.⁶⁰ This means that also staff members need to be entitled to immunities. The scope of these immunities depends on the functions of the organisation. As States grant immunities to staff members in the interest of the organisation, these immunities are not for the personal benefit of the individuals themselves.

In the past States granted staff of international organisations a diplomatic status, or they treated them as if they were diplomats. However, the position of the staff of an international organisation fundamentally differs from the position of diplomats.⁶¹