--<< " The problem, though, is that concessions to Russia on influence in former Soviet countries would mean abandoning allies that have aligned with the United States and Europe since the early 1990s......we cannot abandon those nations that have stood by us since the end of the Cold War, and at the same time realizing that Russia will be instrumental.......to the Iranian nuclear problem.
Russia is just as wary as the United States and Europe when it comes to the prospect of Iran possessing nuclear weapons

Since Russia’s long-term interests are in the areas that once belonged to the Soviet Union, and not in the Middle East, there is some room for dialogue and compromise.
Iran is of secondary importance to Russia, and the possibility exists that the West, led by the United States and Europe, could come to a mutually beneficial agreement with Russia that would return Iran to isolation and increase the pressure on Tehran to come clean

Above, quote from article.