In three decades, the Shiite Islamist movement known as Hezbollah has become a kingmaker and spoiler in Lebanon’s politics, as well as in decisions of war and peace. Here is a short history.

A Shiite Awakening: 1960–82

Lebanon’s Shiites, long the country’s poorest and most downtrodden community, come to political self-consciousness starting in the 1960s under Musa Sadr, a charismatic Iranian-born cleric. Meanwhile, the Shiite heartland of southern Lebanon becomes a battle zone after the Palestine Liberation Organization migrates there from Jordan in 1970. Its presence catalyzes sectarian rifts across Lebanon, and a complex civil war breaks out in 1975. Some Shiites blame the Palestinians after Israel invades southern Lebanon in 1978 and again in 1982. But Israel’s continued military presence, coupled with the spread of Islamic revolutionary fervor from Iran, soon changes that.