Yes Hezbollah might back a loser by supporting an undemocratic regime. However, what might emerge from Syria is a democratic regime that will work to regaining its national pride and restore the Golan Heights to Syrian soveriegnty. Another issue is. If Hezbollah is out of the picture in the future (implausible, but lets consider it), who can protect Lebanon from any future Israeli attack? The US keeps the Lebanese national army weak so as to retain Israel's hegemony in the area.
Mexico: Death toll 27 after truck hits religious procession (AP)
from the article: 'Hezbollah preparing for war against Israel to protect Syria's Assad'