Most of this article in National Interest (which I’m not too familar with) is an opinion piece about Iran sanctions, but a little more than half way it does a good job explaining the rationale behind the UN Security Council.

The UN Security Council is the most important multilateral institution engaged in global governance and cooperative rule-setting. Created in the aftermath of two successive and catastrophic world wars, the council’s legal structure of giving veto power to the major world powers has helped maintain peace between major powers for over seventy-five years. Its decisions mark the highest level of international law.

The raison d’être of the UNSC is to prevent the unilateral use of force by countries. The council relies on consensus decision-making among the five permanent members, ensuring the world’s most powerful countries are constantly in dialogue over pressing security matters. The council’s approval is required to launch wars and the resolutions it passes are binding on all UN members.

Crucially, the veto power the UNSC affords the United States, China, Russia, the UK, and France gives these leading powers a stake in the global order. This helps obstruct zero-sum competition from taking hold among them, which could easily spiral into the kind of worldwide conflicts that reaped immense suffering in the last century.

National Interest

So, one way to state the purpose is to avoid cross-border aggression by major powers against other major powers, because such aggression by any one would automatically be opposed by the other four. No one country is so powerful that the balance of power would be in its favor.

To have a future, the Security Council clearly needs to be expanded to include today’s most powerful countries. It is unlikely it could kick off less powerful countries already there (looking at you, England and France). However, there is some limit to how many parties could be expected to reach consensus. How many? We need more than 5, and more than 10 seems like too many.

How do you define “powerful”? How about a formula? I pulled stats on GDP (at purchasing power parity) from the CIA World Factbook. GDP correlates to economic power, and potential though not necessarily military might. The top 10 look like this:

1	China
2	United States
3	India
4	Japan
5	Germany
6	Russia
7	Indonesia
8	Brazil
9	United Kingdom
10	France

That would include all the current members, plus add Japan, Germany (news flash: WWII is over!), India, Brazil, and Indonesia (hands down the world’s most populous and powerful nation that westerners never think about.)

Who barely misses the cut? #11-15 are Mexico, Italy, Turkey, South Korea, and Spain.

What if we decided actual military spending mattered. I pulled those numbers, gave 50% weight each to GDP and military spending, and it looks like this:

United States

China

India

Russia

Japan

Saudi Arabia

Germany

United Kingdom

Brazil

France

So this would trade Indonesia for Saudi Arabia, which seems odd. If you rate GDP 75% and 25%, you keep Saudi Arabia and Indonesia and leave out France. That seems like a non-starter.

Giving 10% weight to military spending doesn’t change the top 10 compared to straight-up GDP.

So I think my proposal is straight-up GDP. To summarize, it wouldn’t cut out any current member, and would add Germany and Japan, major developed countries and economic powers who lost a war 70 years ago, and major developing countries India, Brazil, and Indonesia. It would be harder to reach consensus with 10 than 5, but the effort of adding these important voices to the conversation would be worth it, and any hard-won consensus would have more legitimacy as representing the majority of the world’s power.