While Iran continues to espouse support for Syrian President Bashar al-Assad on the surface, there are serious undercurrents within the Iranian leadership which portend an about face on this position.
With the recent news that Assad will not step down regardless of Western pressure -- news that the world thought Iran would readily embrace -- it appears the Iranians are instead taking this to mean Assad will now remain in office long enough to see his power and effectiveness diminish over time. Such a scenario will eventually end in triumph for the various factions in the Syrian opposition.
An unnamed Iranian journalist claims that Iranian leaders are now looking at what Iran will lose if the Sunni Muslim rebels succeed in overthrowing Assad: a situation that would leave Shiite Muslim Iran in a state of isolation.
This would also cost Iran some of its "anti-Israel alliance" and could potentially leave Iran looking like a hindrance to change in Syria. Iran cannot afford these black eyes internationally at a time when they are already facing increased scrutiny because of their nuclear ambitions.
Iran has strong ties with Assad at this point in the conflict. They have "acknowledged sending Revolutionary Guard advisers to Syria," and they have been accused of arming Assad's security forces.
This posture has worked up till now. But with Assad vowing to stay put till the bitter end, Iran is starting to rethink where they want to be standing when that end comes.