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The Middle East is riven with fault lines. Conflicts between Israelis and Arabs, Persians and Israelis, Arabs and Persians, Sunnis and Shias, Islamists and liberals, and democrats and Khomeinists are all stuck in a holding pattern that isn't sustainable. The region is in a deadlock and will likely remain so until something big and probably violent unjams it.

Because of its extraordinary diversity, almost every major political current in the Middle East echoes in Lebanon. In the past, Arab Nationalism and Palestinian "resistance" blew through the place and left swaths of wreckage before passions cooled. Thanks to Hezbollah, the country is still a front line in the Arab-Israeli conflict – and that's because the Iranian-backed militia is the tip of the spear in the...