Nicolas Nassif’s very insightful analysis of the reasons for the Syrian government’s cohesion here:

“The Syrian army is the president’s army and it falls when he falls.

Perhaps herein lies the West’s, and especially the United States’ insistence, on a political transition that results in Assad stepping down, while preserving the army’s unity to avoid the repetition of the 2003 Iraqi scenario. 

And because the Syrian army is an ideological army controlled by a solid command and blind loyalty, this majority-Sunni army managed to fight the Muslim Brotherhood and Salafist militants, who are also Sunni, without disintegrating or collapsing.

A telling statement, attributed to the deputy defense minister Assef Shawqat that he then shared with a Lebanese figure who visited him 48 hours before his assassination on July 18, reveals the substance of the confrontation that the army is engaged in.

Shawqat said to his Lebanese interlocutor, “We will not allow the Muslim Brotherhood to take what we prevented them from taking in 1982.”