It is easy to see that global organizations will take over the management of most aspects of human governance, but there are question marks over the political form that they should take.
It is a frequently heard criticism that existing organizations of global governance lack democratic legitimacy, and at first glance this appears to be objectively true. Almost all of the really powerful global organizations - the OECD, the UN, the WTO, the IMF, the World Bank, the IOC – have nation states as their members or contracting parties. They are democratic only in the sense that those member states are themselves democratic, which is true of most but not all of them. And it is far-fetched to suggest that an American citizen has any tiniest shred of involvement in the doings of, for instance, the WTO. To be fair, in the US in particular, there is some political resonance in questions such as the funding of the OECD, but it is limited to the Beltway. Your average Kansas City, Mannheim or Delhi resident has probably never heard of the OECD.
It's also an issue that the 'multilaterals' are monopolies. Nation states have been good at competing with one another, but it's a curiosity of the modern world that, other than in economic achievement, competition (even the little remaining competition between nations, which may have been driving social evolution) is being legislated away by the globalization process. Nowadays it is 'managed' competition. Worse yet, the leadership of some of the key international organisations could almost be described as oligarchic (the International Olympic Committee, for instance). The leadership appointment processes for the IMF, the United Nations, the OECD and the WTO are certainly not transparent. They are not quite as opaque as the appointment of a new Pope, but for the casual observer, there is not much in it.
It's not easy to see how things could be very different. It seems absurd to suggest that anything resembling elective democracy could operate in the selection of a boss for a global organization among the 8 billion – soon to be 20 billion – human beings who are affected by its workings, at least given the present methods that are used to conduct elections, and the almost complete ignorance of most individuals about the organizations concerned. However, both of those situations may change in future. The Internet is perfectly suited to conducting very wide-ranging polls (it's full of them, actually); and it is also likely that knowledge about global governance will come to be a prominent part of future educational curriculae, not to mention the role that the Internet itself will play in educating its users on such subjects. But we are talking 20 years for the Internet to come to function as a channel for focusing informed, global opinion on governance issues; and it may never be more than a partial help.
Pending the birth of a Greek-style global democracy, we are probably stuck with the present system, although one can imagine improvements, particularly as regards transparency. Surely no one will seriously suggest introducing competition into global governance (wars could be seen as a kind of competition between nation states, but they don't do much good for the poor souls who inhabit them). Two United Nations in competition with each other would be as much a recipe for disaster as two equally sovereign governments in one country. That is usually called a civil war.
The opponents of such organizations as the IMF, the OECD and the WTO are probably influenced as much by a perceived lack of transparency in their proceedings as by disagreement with their fundamental goals. Perhaps there is a place for an international Code of Conduct for the Governance of Global Organizations? It would have to have a rule-based multi-nation structure (like the WTO and not like the IMF), and would focus on the transparency of its client organizations, ensuring adequate leadership selection procedures, reporting on alleged fraud or maladministration, criticizing abuses such as the OECD's notorious wine cellar (how dare they drink Chateau Margaux at your expense?) and the like. Currently there is no body to investigate or control the behaviour of the global organizations, which not surprisingly get out of line, and then investigate problems internally, which lacks credibility. The United Nations was damaged by the oil-for-food scandal, and its own, internal investigation was always going to look like a whitewash. The Global Court Of Governance Auditors (GCOGA) – you read it here first!
In fact, the need for a global auditing function is an idea whose time has come. Matsushita, Schoenbaum and Mavroidis 1 suggest the creation of a peer review group in the WTO 'that would examine reports of the Appellate Body, criticize them if there is any problem of interpretation and periodically publish the results'. So far, so good, but the review group needs to be external, not internal. The GCOGA would have sections for each significant global body, completely transparent procedures, and an Appeal Tribunal.
1 Matsushita, M, Schoenbaum, T J, and Mavroidis, P C (2006) The World Trade Organization - Law, Practice and Policy, Oxford International Law Library