[Capt. Tom]

Assad may lack the required aid to prevent the collapse of his government, potentially delivering weapons into the hands of ISIS that would dwarf those they captured in Iraq.

The Sunni fighters who want Assad ousted outnumber Assad and his Alawites.
Assad will have to depend on Shia Iran for support if the Sunnis concentrate their forces in Syria. Many Sunnis are tied up in Iraq now.

But will Iran put troops on the ground in Syria. After all Assad is an Infidel collaborator, i. e. Russia.
I believe Iran should have a plan to take over the Shia city Baghdad in Iraq. I would expect Iran to try that, especially if Assad falls to the Sunnis - tom

[AlaskaErik]

But will Iran put troops on the ground in Syria. After all Assad is an Infidel collaborator, i. e. Russia.

Iran also collaborates with Russia, so that shouldn't be an issue.

[Reaganez]

Iran’s proxy Hezbollah is putting boots on the ground. They are much more effective than 30 years ago.

Alawites are only ~10% of the population. Since ISIS is in the habit of slaughtering minorities and Wahabis are not much better Assad has also drawn support from Armenians,Kurds and other minorities. All told about ~27% of the population are minorities(including Alawites).Strategically not ideal, but enough to win with resources and effective leadership.