In the middle east Iran* probably has the greatest geopolitical reach of any country within the region. Through Hezbollah they have an enormous impact on Syria, Lebanon, the Palestinian territories and even Israel. If the al-Assad regime falls Iran has the most to lose as suddenly it would become far more difficult, logistically and otherwise, to provide support to its groups in the Levant.
This explains why Iran is threatening action if the US bombs Syria, for example.
The Putin regime has certainly shown itself capable of significant international "hijinx" (such as assassination, vote rigging, etc.) but overall this doesn't fit their MO.
(*: note that when I say "Iran" here I am talking about the current Iranian regime, very much not the Iranian people.)
This explains why Iran is threatening action if the US bombs Syria, for example.
The Putin regime has certainly shown itself capable of significant international "hijinx" (such as assassination, vote rigging, etc.) but overall this doesn't fit their MO.
(*: note that when I say "Iran" here I am talking about the current Iranian regime, very much not the Iranian people.)