The chapters collected in this Cambridge Companion together demonstrate a few things about the law of international organizations – and law generally perhaps – that may not always be realized. A first point to note is that international organizations are active in nigh-on all walks of life, as these chapters suggest. There are few human activities with which international organizations have no point of contact. Whether it concerns energy provision or the movement of persons across the globe; whether it concerns disarmament or financial stability or the governance of resource extraction, international organizations are often involved in one way or another. And even in those policy domains where there is no single overarching international organization (most conspicuously perhaps the heavily fragmented domain of environmental protection), there are nonetheless entities active which may not generally be considered international organizations (largely because their founding fathers shy away from using that label), but which are remarkably similar to international organizations in all but name.

Even the most casual observer of international organizations must at times be puzzled. It is puzzling to realize, for instance, that regardless of the public outcry over nasty acts done on the watch of some international organization or another, nothing ever seems to happen: accountability is much-discussed, but rarely materializes. It is somewhat mystifying that for all the discussion of the reform of international organizations and of their policies, and for all that these are often amended, nothing much ever seems to change. Likewise, few international organizations have lawmaking powers properly so-called, and yet international organizations seem to be highly influential. By the same token, international organizations often engage in co-operation with one another without anyone noticing it, and seemingly without having strong authorization to do so. And it must be puzzling to realize that the law tends to treat all international organizations in much the same way, regardless of whether they work for the global common good or are better seen as interest groups for a particular group of states; regardless of whether they serve a global cause or manage a particular industry; and regardless also of the sort of activities they engage in – whether they occupy themselves with questions of peace, security and disarmament or are, effectively, institutions of higher learning set up as international organizations.

Behind the newspaper headlines, often an international organization can be discerned. Sometimes the connection remains somewhat hidden. When the USA chides Turkey for procuring weapons from Russia, it suggests that US manufacturers should be privileged because Turkey is a member state of NATO, the US-driven Atlantic security organization. When Poland aims to withdraw from the Istanbul Convention, outlawing domestic violence, the Council of Europe expresses concern, if only because the Istanbul Convention was concluded under its auspices. And when it turns out that mailing parcels from certain countries is cheaper than mailing similar parcels domestically, it is not always immediately realized that this may have something to do with postal rates negotiated within the Universal Postal Union.

When international organizations were first established in the nineteenth century, they were largely seen as self-contained entities, performing functions for their member states but not much else. What was relevant was the set-up of each and every individual organization; nothing more, nothing less. The idea of such organizations entering into arrangements with other organizations, or even with third states, was for a long time considered anathema.

The present chapter, and the two that follow, will largely address the position of international organizations vis-à-vis the outside world, discussing three broad issues. First, this chapter will be devoted to whether organizations can conclude treaties, and on what basis. The next chapter will discuss with whom they enter into relations, and the subsequent chapter will analyse what will (or may) happen if something goes wrong in relations between an international organization and some other actor.

An oft-heard complaint about the UN is that it does not deliver what it promises. The organization carries the promise of universal peace and security, but sometimes fails to show up in crisis situations, or shows up too late, or does too little. One of the standard replies on the part of the organization is that it lacks the funds, and could do a lot more if only its member states would pay their contributions, and would pay them on time and in good order. And that, in turn, signifies that, however esoteric the topic may seem, the financing of international organizations is of the utmost practical relevance. As Singer put it in the early 1960s: ‘Until the policy decisions of the various organs are translated into budget items, there is no visiting mission to encourage Togoland’s movement toward eventual self-government, no ceasefire observer in the Middle East, no rehabilitation commission in South Korea, and no Public Administration advisor in Santiago.’1