The Shanghai Cooperation Organization (SCO) may soon expand to include Pakistan, and more importantly Iran. Iran is already an observer nation, but full-fledged membership would definitely have a big impact on the region, as well as any future role for the SCO. Larison disagrees:
Granting Iran membership would be seen in the West as a provocative move, but a good question is why anyone should be provoked by it. The SCO is not a full-fledged military alliance or defensive pact, and it has existed primarly as a mechanism to consolidate Russian and Chinese political and economic influence in Central Asia. At the moment, it is a limited security and economic structure.
This is all true – the SCO isn’t even on par with the CIS or other limited regional IGOs. But seeing as one of the main purposes of the organization is to provide China and Russia a multilateral forum for pressuring much of Central Asia, this only increases their ability to do so. I think the way to look at this isn’t so much as Iran gaining influence and legitimacy, but rather another big country on the periphery of Central Asia able to provide additional leverage for Russia and China. A shrinking of Central Asian security.
But the most interesting wrinkle might be that for Iran it can’t be about oil, unless they know something about their reserves we don’t. Larison’s observation that it’s Russia pushing for Iranian membership with the Chinese more reluctant points to some interesting energy politics. Could Russia be looking at Iran as their Kazakhstan?
I wouldn’t hold your breath. Iran applied for a membership in early 2008, and it hasn’t received its membership yet. Here’s a decent analysis on what’s what (from 2009):