Doyle McManus writes:  The Middle East has no shortage of conflicts to worry the rest of the world: the wars in Afghanistan and Iraq, the nuclear ambitions of Iran, the stalemate between Israel and the Palestinians. And now, add an old trouble spot to that list: Lebanon. On the one hand, Lebanon's economy grew by a dizzying 9% last year, the strongest pace of any country in the region. Its feuding religious and political factions have joined in a power-sharing agreement that seems stable. And it's even selling itself, with some success, as a chic destination for European and American tourists. But as I discovered on a visit to Beirut last month, the Lebanese are certain all this good fortune can't last. They're convinced -- not without reason -- that the confrontation between the U.S. and Iran will spill over into another war between Israel and Lebanon.  Just inside Lebanon's southern border, where Israel and the Shiite Muslim militia Hezbollah went to war in 2006, Iran and its ally, Syria, have been helping Hezbollah rearm. The radical militia, which runs southern Lebanon as its own mini-state, reportedly has obtained Iranian-made missiles that can reach Tel Aviv, and Hezbollah's leader, Sheik Hassan Nasrallah, has promised to strike at Israel at a time and place of his choosing.  Israel isn't taking the threat lightly; its pugnacious foreign minister, Avigdor Lieberman, recently warned that Israel might use the next war to try to topple Syria's authoritarian regime. – Los Angeles Times