Russo-Iranian trade is close to $2 billion annually — and is comprised mainly of deals for Russia's nuclear and defence industries. But economic gains alone do not explain Russia's reticence to turn up the heat on Iran. In the great and complex energy game Russia is playing with Europe, Iran has a pivotal role, as an important ally which could help Moscow bully the Caspian Sea nations and potentially set up an energy cartel that would keep Europe in check.

Then there are cold, raw power considerations. Russia sees Iran as its entry point into the Middle East-a gateway to regaining lost influence in a key strategic region. Russia does not see a nuclear Iran as an existential threat. It knows Russia ranks low in Tehran's list of mortal enemies. Pushing the regime too far on the nuclear issue might engender the kind of sea-change in Tehran that could damage Russia's long-term interests. The last thing Russia wishes to see is Iran's return to being an ally of the West.

But this does not mean that Russia necessarily views a nuclear Iran with favour. But given all of the above, why should Russia be of any help?

Multilateralists may answer that Russia will ultimately come around because it cannot possibly want a nuclear Iran on its doorstep. This may be the case, but it does not follow that Russia will help hinder this eventuality. Russia may dismiss Iran's technological prowess and think that Tehran will never master the required science to build a bomb. They may also believe that Israel or the US — or both — will attack and destroy the Iranian programme before that could happen. So why squander so much political capital in Tehran, when others will fix the problem at no cost to Russia? Better to be freeloaders, benefiting from a military attack politically (no nukes on Russia's borders) and economically (Russian contractors will clear the rubble and rebuild the damaged infrastructure).

In short, Russia benefits from a middle ground between the absence of war and the absence of peace. It will continue to play its cards and leave the West stuck there. Its interests are not the West's. More efforts to bring Russia on board and thus deny cover for China will be a waste of time.

Bottom line — don't wait for Russia.