This piece over at RealClearWorld about Russia’s policy toward Iran is preaching the choir here at this blog:

As long as Iran remains a pariah state, Moscow can use Iran’s isolation to sell them their outdated jets and secondhand products, which other countries would not buy from them. This theory has its merits. According to BBC Persian, Russia’s exports to Iran since 2006 have more than doubled from $864 million to $2.5 billion in 2008.

Moscow’s ties to Tehran’s hardliners balances out Washington in the region.

Furthermore, with its policy of defending Ayatollah Khamenei’s administration, Russia has become an invaluable ally to Supreme Leader. In fact, after Syrian President Bashar Al Assad, Vladimir Putin and Dmitri Medvedev are considered to be the second most influential voices inside Iran. This influence was put on display during Putin’s visit to Tehran in November 2007. All he had to do was to place a proposal regarding the nuclear standoff on Khamenei’s table. In less than a day, current Majlis Speaker Ali Larijani and President Ahmadinejad were at each other’s throats. The dispute ended with Larijani’s resignation as the Secretary General of the Supreme National Security Council; signaling that Russia’s position in Tehran is taken very seriously.