The field hospital in the dark and dirty alley behind the Hardee's in Cairo's Tahrir Square is up and running again, just as it was last February. Once more, volunteer medics wearing gloves and surgical masks--to mitigate the sting of tear gas--lean over the wounded and dying activists ferried in on the backs of motorcycles. The square itself is an equally familiar scene: Egyptian protesters clash with security forces, exchanging rocks and Molotov cocktails for tear gas and bullets, as others lead chants for freedom. But now the regime change they are calling for is embodied not in Hosni Mubarak but...