Hezbollah is hardly defenseless, it keeps Israel in total check with a veritable deterrent strike capability, a very high price. ' As for responsibility, Israel customarily uses assassination/death as a military/political tool, and repeated attempts to kill leaders, even 80 yr old wheel-chair bound types by dropping 500lbs bomb on living quarters killing children in the process. Anyone not know this? So claiming Israel responsible, even if not in this particular case, is entirely suitable. Fortunately, unlike Israel hotheads, Hezbollah/Lebanon will soon find out ... and if they can't that would only be stronger evidence it was Israel.
Israeli army lifts closure on West Bank town of Qabatiyah after three days (Haaretz)
from the article: Hezbollah: Israel assassinated organization's arms chief near Beirut