I believe Iran collaborates with Russia because Iran wants to get nuclear weapons to wipe out Israel and other Infidels.
Russia can help them achieve that nuclear ambition.
Also Russia is no friend of ours.
Assad and his Alawites are a heretical Shia sect and don't share the same religious beliefs as Iranian Shias. Iran doesn't have to come to Assad's rescue , unless it is to Iran's advantage. - Tom
No country, save for the USA under Ds,does anything unless it is to their advantage.
Russia and Iran don’t have to prop up anybody but until now they support Assad.
In 1970s Musa Sadr, an Iranian cleric and head of Lebanon’s Shiite community,issued a fatwa declaring Alawites part of Shi’ism. He formally announced the acceptance of Alawites as Shiites, a move that significantly opened the way for the sect’s recognition within the general Shiite community.