Mr. Imad Mugniyeh, one of the world¡¯s most wanted men, was killed this week in Damascus. Mr. Mugniyeh, a commander of Hezbollah, the militant Islamist group, has been sought for his role in a series of terror attacks around the world that killed hundreds of people. Although no group claimed responsibility for the killing, Israel has been blamed. Retaliation is sure to follow, for which Mr. Mugniyeh would likely be proud.

Mr. Mugniyeh has been accused of planning the 1983 bombings of the U.S. Embassy and a marine barracks in Beirut, which claimed hundreds of lives, the hijacking of a jet in 1985, during which a U.S. Navy diver was murdered and dumped on the tarmac, along with a number of other high-profile kidnappings.

Until 2001, U.S. officials alleged he was involved in more terrorist attacks against Americans than any other person. Israel charges him with helping plan the 1992 bombing of its embassy in Buenos Aires, which claimed 29 lives, and the 1994 bombing of a Jewish community center in the same city that killed another 85 people, as well as smuggling arms from Iran to Palestinian resistance groups. He was said to have been involved in the bombing of the Khobar Towers in Saudi Arabia in 1996.

Mr. Mugniyeh was killed when a bomb exploded under his vehicle in a Damascus neighborhood. No one took responsibility for the killing, but Israel tops the list of suspects. Israeli officials denied involvement, but that is unlikely to affect the thinking of its enemies. Iran quickly blamed Israel for the assassination. Hezbollah denounced the killing and hailed his martyrdom.

Mr. Mugniyeh¡¯s death comes at a sensitive time. Lebanon is commemorating the third anniversary of the assassination of former Prime Minister Rafik Hariri; Syria has been blamed for his death and the prospect of clashes between his supporters and Hezbollah ¡ª which enjoys support from Damascus ¡ª could further destabilize a country. Just as worrisome is the prospect of retaliation by Mr. Mugniyeh¡¯s followers against Israel. A desire for vengeance, not proof of involvement, is all that has been needed to unleash Mideast violence.