The situation in Egypt is, as they say, fluid, with rioting in Cairo, protestors clashing with police, vehicles set afire and a prominent Egyptian who returned home to foster democracy placed under house arrest. The president, Hosni Mubarak, has not been seen nor heard from in days. His wife has, by some reports, fled the country. The world is watching and no one can predict what may happen next.

But a scholar of Middle East politics and history has pointed out a key element in the general upheaval.

I have been watching and paying attention to the situation in Egypt for four days now, and I have not seen one radical Islamist slogan, said Rashid Khalidi, Edward Said Professor of Modern Arab Studies at Columbia University. I have not even seen any bearded guys.

Khalidi said that the agitation in Egypt is not based in radical Islam, but in a widespread desire for political and economic reform.

The people do not want a monarchical system. They do not want Mubarak appointing his son as his successor, Khalidi said. They are demanding a greater degree of social justice. They are demanding constitutionalism.

The Egyptian people see the corruption and the cronyism of the Mubarak regime and they want it to stop, Khalidi said.

There has always been a disparity in the distribution of wealth in Egypt, but that disparity has increased markedly in recent years, and the people are fed up and frustrated with it, he said.

Khalidi said the Mubarak regime has ignored the people's frustration in the past and ignores it now at their peril.

We have been sold a bill of goods, not only the Egyptian people, but people in the United States and around the world have been sold a bill of goods, Khalidi said. We have been told that we must accept a corrupt and autocratic regime like Mubarak's, or we will get a radical Islamist revolution. But that is not the case in Tunisia, and that is not the case in Egypt.

Khalidi said that there is a radical Islamist movement in Egypt, but it is not behind the current unrest.

The Islamists have tried to ride the wave but, so far at least, they have not succeeded, he said. We have not seen them in Egypt, and they were nowhere to be found in Tunisia. This is not a religious upheaval. This is political and economic.

Mohamed ElBaradei, a Nobel Peace prize winner and the former head of the International Atomic Energy Agency, returned to Egypt, his native land, on Thursday, to lend support to the democratic agitation. He joined the street demonstrations, received a soaking from the water cannon of riot police and, on Friday, was placed under house arrest.

There is speculation that ElBaradei has returned to put himself forward as a political leader to challenge the Mubarak regime. Presidential elections are slated for the fall and the expectation had been, at least until the last few days, that Mubarak will manage the process to raise his son, Gamal, to the presidency.

What effect the current unrest will have on Mubarak's plans remains to be seen, as does the position of ElBaradei, who has not specifically said that he is seeking the presidency.

It is a critical time in the life of Egypt, ElBaradei said to reporters. I wish we didn't have to go into the streets to impress upon the regime that they have to change.

Khalidi said that ElBaradei's role is somewhat complicated.

He is well-known, but he is not universally known. He has been out of the country quite a long time and is viewed as something of an elitist, Khalidi said. Some may suspect that he is there also to ride the wave. The people of Egypt have brought about this movement, not ElBaradei.

On the other hand, Khalidi said, if this movement gets as far as regime change, ElBaradei may be the kind of figure who can galvanize the people behind him.

Khalidi was loath to make predictions, but he did say he thought the Mubarak regime's days are numbered.

I do not think the people are going to calm down. Something is going to have to change. The question is: What vision of Egyptian society is going to prevail? Khalidi said. As ElBaradei himself has said, 'the Egyptian people have broken the barrier of fear.'