For Ike, it was Lebanon’s civil war and Israel’s Sinai invasion. For Lyndon Johnson, it was the 1967 Six-Day War. For Nixon, it was the 1973 war. For Carter, it was the Iranian Revolution. For Ronald Reagan, it was Lebanon. For George H.W. Bush, it was Iraq. For Bill Clinton, it was Al Qaeda and Afghanistan. For George W. Bush, it was Iraq and Afghanistan. For Barack Obama’s first term, it was Iran and Afghanistan, again. And for Obama’s second term, I fear that it could be the full nightmare — all of them at once. The whole Middle East erupts in one giant sound and light show of civil wars, states collapsing and refugee dislocations, as the keystone of the entire region — Syria — gets pulled asunder and the disorder spills across the neighborhood.