Iran in Syria: Deal-maker or deal-breaker?

Since the outbreak of the conflict in Syria, Iran has been a steadfast supporter of Bashar al-Assad's regime, and ensuring its survival is Iran's primary objective. This is unsurprising, given that Tehran needs a friendly regime in Damascus to protect its strategic interests in the region. At the same time, there is an expectation of more constructive engagement from Iran following the signature of the nuclear deal with E3/EU+3 countries.