What is one way in which the israeli-palestinian conflict affected lebanon?

Palestinian refugees flowing into Lebanon contributed to political unrest in Lebanon.

Lebanon became independent of French control in 1943 and had a coalition government representing different groups.  The country had undergone a civil conflict between Muslim and Christian groups already in the 1950s.  A national reconciliation government had been formed in 1958, maintaining a fragile peace between the Maronite Christian and the Sunni and Shia Muslim communities.  Hundreds of thousands of Palestinians became refugees after "al Nakba" (the catastrophe), when Israel took over their land in Palestine.  Lebanon was one of the places where refugees went, and the number continued to grow.  By 1967, Palestinians made up 12% of Lebanon's population.  In 1970 the Palestine Liberation Organization (PLO) made Lebanon its base of operations.  All of this only contributed to tension within Lebanon.  A bloody civil war in Lebanon began in 1975, with PLO fighters battling Maronite Christians.  Alliances and involvement by various other factions followed.