By design or not, key leaders of Lebanon's opposition bear considerable responsibility for much of what happened because they have helped to create an environment conducive to the breakdown of public order.

Assuming that they do not want a resumption of the disaster that unfolded in Lebanon between 1975 and 1990, these same leaders have a clear duty to help prevent it. By threatening unspecified "street action," Sayyed Hassan Nasrallah of Hizbullah, Speaker Nabih Berri of Amal, MP Michel Aoun of the Free Patriotic Movement and former Minister Suleiman Franjieh of the Marada Movement, among others, have encouraged those with grievances against the state to imagine that harming the interests of their fellow citizens is an acceptable method of making their point. It is essential that the legions of increasingly angry young men be relieved of their misconceptions - and that this be done by those who have allowed them to go astray.

No one has more power to accomplish this than does Nasrallah: His party is by far the opposition's (and the country's) largest, its organizational capabilities are unmatched, and other groups are less likely to take assertive steps without at least tacit support from it. It may be true that Sunday's protests took place without official opposition encouragement, but if that is true, there is even more reason for Nasrallah to step in, and to do so in unambiguous fashion. If this means issuing a fatwa banning destructive tactics under the pretext of political protest, so be it: Failing to rein in the hotheads can only expose Hizbullah's reputation to further criticism and the country as a whole to additional peril.

The opposition is certainly not alone in having obligations regarding Sunday's tragedies. Many people will be watching closely to see if the government can conduct an effective investigation into how and why so many people died, and if it can alleviate the conditions that fuel unrest. Unless the soaring tensions that led to the riots are brought - and kept - under control, however, it is just a matter of time before one of these incidents gains the necessary momentum to defy any and all attempts to restore calm. If and when that happens, it will not matter how an investigation turns out or how long the power stays on because the attention of most Lebanese will be focused on the basic task of staying alive.