Egyptians have been here before. The so-called Cairo spring of 2005 briefly lifted hopes of peaceful reform and open elections. Those hopes died, like autumn leaves, blown away by a withering sirocco of regressive measures and reimposed emergency laws. Food and price riots in Mahalla el Kubra in 2008 briefly raised the standard of revolt again. They were quickly suppressed.
But Tuesday's large-scale protests were different in significant ways, sending unsettling signals to a regime that has made complacency a way of life. "Day of Rage" demonstrators in Cairo did not merely stand and shout in small groups, as is usual. They did not remain in one place. They joined together – and they marched. And in some cases, the police could not, or would not, stop them.
This took President Hosni Mubarak and his ministers way out of their comfort zone. Interior minister Habib al-Adli had said earlier he held no objection to stationary protests by small groups. But marching en masse, uncontrolled and officially undirected, along a central Cairo boulevard, heading for the regime heartland of Tahrir Square – this was something new and dangerous.
The protests' organisation was different, too – recalling Tunisia, and Iran in 2009. The biggest opposition grouping, the banned Muslim Brotherhood, for so long a useful Islamist idiot manipulated to bolster western support for the secular regime, declined to take part. Egypt's establishment rebel, the former UN nuclear watchdog chief, Mohammad ElBaradei, also steered clear.
Instead an ad hoc coalition of students, unemployed youths, industrial workers, intellectuals, football fans and women, connected by social media such as Twitter and Facebook, instigated a series of fast-moving, rapidly shifting demos across half a dozen or more Egyptian cities. The police could not keep up – and predictably, resorted to violence. Egypt's protests already have their martyrs, killed by police or burned to death by their own hands. But Egypt does not yet have a Neda Agha-Soltan. Pray it never does.
The language and symbolism were different, too. "Enough, enough (kifaya)!" they shouted in 2005, giving a name to the movement for change. Now the message is: "Too much, too far, for too long!"
"Mubarak, Saudi Arabia awaits you," the demonstrators chanted, referring to the refuge of the Tunisian ex-dictator Zine al-Abidine Ben Ali. "Out! Out! Revolution until victory," shouted a group of mothers, babes in arms. Across Cairo, Alexandria and beyond, the banners of the Tunisian intifada waved liked semaphore flags, wishfully signalling an end to the ancien regime.
But Egypt is not Tunisia. Egypt is a much more efficient police state, a much harder nut to crack. Its leader is as tough and as canny as an old fox. Its military and ruling elite is in hock to the Americans to the tune of $2bn a year – and the American republic, itself born of revolt, has no love of revolutions. Mubarak, 82, has held power for 30 years. He is his own, and Washington's man. According to WikiLeaks cables, he likely plans to die in office – and then hand over to his son.
There is no revolution in Egypt, yet. But, hypothetically, if Mubarak were to fall, the consequences would be incalculable – for Israel and the peace process, for the ascending power of Iran, for US influence across the Middle East, and for the future rise and spread of militant, anti-western Islam. And not least, for 80 million Egyptians.
"Our assessment is that the Egyptian government is stable and is looking for ways to respond to the legitimate needs and interests of the Egyptian people," US secretary of state Hillary Clinton declared on Tuesday night. They thought that about Ben Ali's Tunisia, too. Clinton's hurried words show how worried they are.