It is Russia that has and is chummy with Iran. They have used Iranian bases to attack Syrian rebels. Russians invited Iranian leaders to Russia this year. Russia also broke its promise to the US to stop Assad from owning and using chemical weapons. It was the Republican hawks, including McCain who wanted to arm the Muslim Brotherhood against Assad and not Obama.  US Army reported last week that Russia is supporting the Taliban in Afghanistan. It is now time for Trump to twist Putin's arm-- let's see how he does.