This is a much suggested thought (for example, here). Basically the idea is that there are two interpretations of Western inaction so far. Either Obama has just been cluelessly dithering over what to do. Or, much more cleverly, Obama has been waiting to lay a trap for Iran and Hezbollah, luring them into escalating their involvement in Syria only to ensnare them in a grinding, never-ending guerilla war.
Well, count me among the skeptics concerning this idea.
First this position takes Nasrallah’s rhetoric of being wholly committed to Assad’s survival at face value. But more than simple loyalty to Assad, it is much more likely that Hezbollah is keeping a keen eye on its specific interests in Syria, in particular the weapons Assad is supplying. As such, should things really go sour for Assad in Syria, it would not surprise me for Hezbollah to simply abandon its commitment and withdraw into its impregnable Lebanese base of support.
In this regard we should also consider Hezbollah’s key role as the ‘mobile cavalry’ of the Russian-Iranian axis. In being a high-caliber foreign fighting force that is flexibly employable, Hezbollah is of great value to its powerful patrons. In this way, just as it was Hezbollah’s Russian/Iranian patrons that inserted it into the Syrian theater, surely these powers would take care to preserve Hezbollah’s capabilities for future occasions, even if this comes at the expense of ultimately abandoning Assad.
Finally it should not be underestimated how effective Hezbollah could be in a post-Assad Syrian chaos. Without a central authority or specific areas to protect, and with a Sunni insurgency at that point most likely internally divided, it is not at all clear Hezbollah would be the party to suffer from an intractable guerilla foe; rather it could precisely constitute such a foe to any Western-backed party.