In September 2005, more than 180 heads of state and government from around the world will converge on New York city to celebrate the 60th anniversary of the United Nations—and more importantly to decide how to try to save that body from obsolescence. The agenda will include important issues such as the reform of UN budgets, management and committee structures, but the issue inevitably at the top of most minds will be the question of the Security Council's composition. Will the UN body responsible for maintaining international peace and security take on new members, and if so, who?

Reform of the Security Council has long been high on the international agenda, but the only thing everyone agrees on is that the current arrangement is deeply flawed. Many Americans ask why international legitimacy should be conferred by countries that have little responsibility for global peace, such as Cameroon, Mexico, and Angola (all Security Council members at the time of the Iraq war), or by non-democracies such as China. Rich and populous countries like Japan and Germany complain that they are at least as deserving as Britain and France, whose membership emerged from the results of a war that took place over 60 years ago. Many Africans and Latin Americans resent the notion that international peace and security should be decided mostly by Americans and Europeans.

UN Secretary General Kofi Annan argues that the Security Council—currently made up of the US, Russia, China, Britain and France as permanent members and 10 rotating members—will only command respect, especially in the developing world, if its composition is changed. The question is how to change it, and that is where it all gets tricky.

Two rival proposals have emerged. One proposal, sponsored by the self-designated "Group of Four" (Japan, Germany, India and Brazil), would add six new permanent members—the G4 itself plus two African countries still to be determined—as well as four new rotating members. It would thus expand the overall membership of the Council from 15 to 25. Veto rights under this proposal would be reserved for the current permanent five.

The alternative proposal, sponsored by a group of countries that includes Italy, Pakistan, South Korea, and Spain would also expand the overall Council to 25, but would add only nonpermanent members (ten of them), chosen from a group of around 30. Its sponsors argue that it would avoid having to choose among regional rivals for a permanent slot while having the advantage of allowing some of the UN's more important contributors to serve on the Council more often than its smallest states.

Any reform of the Security Council requires agreement from all five permanent members of the Security Council plus two thirds of the General Assembly—128 of its 191 members. And the challenge of winning such support has already led to a furious lobbying effort by all involved.

As permanent, veto-wielding members, the United States and France will play critical if not decisive roles in the outcome of the debates. Washington has said it wants to limit the size of the overall Security Council to twenty and that it will support adding no more than two permanent members, one of which will be Japan. And while President Bush recently reassured German Chancellor Gerhard Schroeder that he "does not oppose" any particular country's bid, U.S. officials have privately—and brutally—made clear that Germany is not on their list.

The White House is still angry with Berlin over its opposition to the Iraq War, and worries that adding yet another European permanent member would mean having to add even more from other regions, further diluting American influence in the Council.

France, on the other hand, supports the proposal to add six new permanent members, including Germany. Paris argues that the wider Council would be more legitimate, and privately calculates that many of the new permanent members (including Germany, India, Brazil and the Africans) would more likely side with France than with the United States on many key UN issues. The French also realize that a rejection of Germany would cause friction between Paris and Berlin and eventually lead to pressure for an EU Security Council seat—instead of a French or British one.

What, then, to do? In my view, the best reform would be a limited one—adding only Japan and India to the permanent group plus about three new rotating members. Japan is a key financial contributor (over $800 million per year, or just under 20% of UN budgets), a responsible democracy and a major player in East Asia. India of course contributes less money, but it is a rising democracy with a growing economy, and an increasingly global player that represents a sixth of the world's population. The case for permanent membership is harder to make for Germany—simply because there are already two EU permanent members—and for Brazil, whose contributions do not stand out relative to other rotating members (or to those of Argentina for that matter).

Adding Japan and India would also strike the right balance between the need for diversity (giving a greater voice to Asia and the developing world) and efficiency (keeping the Council small enough to be workable). Finally, it would be wrong to argue that this option fails to give a voice to regions like Africa, Latin America and the Middle East, as the new Council would include some 13 rotating slots, 30% more than in the current arrangement, most of which would go to representatives from these three regions. Even the current, supposedly illegitimate Council includes a fairly global set of representatives—at the moment Algeria, Argentina, Benin, Brazil, Denmark, Greece, Japan, the Philippines, Romania and Tanzania.

None of the options for Security Council reform is perfect, including the one defended here. And France's desire to expand the Council to acknowledge a more multipolar world and show solidarity with its German neighbor is understandable. But Paris should also realize that if wide support for such an enlarged Council cannot be reached, the result could be a Security Council that is less effective, not more. Certainly if the United States ends up vetoing the Group of Four plan the old Council would remain in being—but its legitimacy would be in tatters.

Let us hope that the emerging debate on this sensitive issue does not turn into yet another bruising clash between Paris and Washington over legitimacy and world order. If a consensus cannot be reached around a workable reform plan, it will be better to have no reform at all.