“Go ahead, make my day.”
This would be catastrophic, and the worst part is he might be right! Iran very well could come to the aid of Syria with missiles not just in the Gulf but also militancy against US soldiers in Iraq and Afghanistan. Their financial support has bought them terrorists willing to hit western targets throughout the ME and probably Europe, and potentially beyond.
The threat seems real, and significant. That said, no one in NATO said anything about military force...the resolution even eliminated the threat of sanctions.