In this process, some truths once considered absolute have perished summarily, including the impunity of the police and the infallibility of Mubarak. Others are quietly reasserting themselves: many Egyptians are accustomed to order, state security owns most of the country's streets, and force often carries the day.

In Tahrir Square, the general's patience was wearing thin. He wanted to inspect the defensive works erected by the demonstrators, and he appeared eager to make a personal show of force.

Surrounded by a personal detail of guards numbering less than a dozen, General Ruweini strode directly toward a barricade fashioned out of metal roofing detritus. The soldiers pushed it over seconds and strode over it.

The crowd surged, summoned by shrill whistles and low thunderous banging of clubs on metal. Young men reassembled the barricade in a few seconds but the general already was inside their cordon, marching through a crowd of hundreds suddenly electrified with fear and anger.

The word spread: the tanks were coming in. The military was going to clear a crucial position, perhaps dealing a death-blow to the protest movement on its 12th day.

A cry rose up from the crowd: "We will die here!"

With relish, the general pushed on through the angry throng. Army snipers kept watch from the roof of the National Museum. One of General Ruweini's bodyguards, close enough to touch, placed his beefy hand on a demonstrator's face and decisively shoved it aside. The general, his faint smile uninterrupted, pulled himself onto a fence to address the crowd. By then it was clear that the tanks were not coming in, but also that the military could be casting about for ways to marginalize Tahrir Square, the regular cries of "The people and the army are a single hand" notwithstanding.

The general extended his hand and patted the air to shush the crowd. A young organizer tried to help: "Let him talk!" the young man shouted. Smiling, General Ruweini clasped the activist's head in one hand, pulled him close, and gently slapped his check. The gesture was paternal, intimate and carried a whiff of menace not lost on the crowd. He seemed to be saying to the young protest leader, See, even you can't control these ribald youths.

To the crowd he spoke firmly, but without shouting. "The military will remain neutral. We will not use force against you. But we need to get things back to normal," the general proclaimed. His tone was new, softened by an effort to persuade uncharacteristic of a security state accustomed for generations only to issuing orders, not explaining them. The general's gesture made clear, though, that the military still feels itself a master among Egyptians.

For the next hour, the general zigzagged among the rebels on Meret Basha Street, directly to the east of the soft-pink National Museum. He argued with the volunteer doctors running a clinic in the street for wounded protesters. He put his arm around one and said warmly, "Can't you move your operations inside the square?" For good measure, though, he made clear his regard for them. "You keep bandaging up people's heads to make it look like they've been wounded. Why?"