For nearly three decades, Egypt's President Hosni Mubarak has been one of the pillars of the Middle East: a fixed point around which everything else revolves.
But more than a year before the next presidential election, uncertainty is replacing stability as the theme of Egyptian politics.
Hosni Mubarak is 82 years old. Rumours of ill health have been vigorously denied. For someone of his age, he pursues a remarkably active schedule.
Engagements are lined up, sometimes almost as a rebuke to those who suggest that Mr Mubarak's energy is fading.
But it is hard to silence the questions over whether a man who will be 83 at the next election is really suited to take on another six-year term in this gruelling job.
Amid this fevered atmosphere, a strange campaign has sprung up to nominate the president's son, Gamal Mubarak, to run for the highest office.
Posters of Gamal alongside his father have been spotted in poor neighbourhoods. Several online campaigns seek to gather millions of signatures calling on him to stand.
In a working-class area, streets bustling with life on a sweltering summer's evening, a small rally is held to collect more signatures. Money has been spent on loudspeakers and posters.
The ruling National Democratic Party (NDP), of which Gamal is a senior officer, insist that neither they nor Gamal himself have organised nor endorsed the campaign.
It is, they insist, a spontaneous grassroots campaign that they are powerless to prevent.
"These campaigns represent individual initiatives, they are in no way related to the NDP. None of the leadership of the NDP has endorsed them officially or unofficially. So it remains a sporadic voluntary activity in society," explained Aley el-Din Hilal, a senior official of the party.
Gamal Mubarak himself has remained conspicuously silent, neither endorsing the campaigns, nor making any attempt to silence them.
So observers of Egyptian politics are sceptical that everything is quite what it seems.
There certainly seem to be plenty of contradictions over these apparently spontaneous campaigns.
Gamal Mubarak is a smart-suited young businessman, who has worked overseas and is linked with a series of business people and reformers who have been injecting a whiff of market capitalism into Egypt's statist economy.
He is known as a child of privilege, who has grown up in the presidential palace, a man who took his wife to the UK for the birth of their child rather than trust an Egyptian hospital.
So it was strange to find the headquarters of the "People's Coalition in support of Gamal Mubarak" in one of the dirtiest, most run-down streets in Cairo.
Even stranger to hear the organiser, Magdi el-Murdy, talking of the need to nominate the president's son in order to move power away from the elite.
But then, as another activist on another pro-Gamal campaign, Magdi Wahba, put it to me: "You don't have to call him the president's son. We can call him a businessman. We can call him educated, very educated, very touched and powerful in our country. In every plan he has, there is always something there for us youth."
Not surprisingly, members of the opposition have their own perspective.
Shadi Taha of the opposition al-Ghad party described the campaign as an attempt to show that the Egyptian public was "begging" Gamal Mubarak to stand.
It was, he argued, one of the "many scandals" of the National Democratic Party.
As for a Gamal Mubarak presidency, it would set Egypt back hundreds of years, he suggested.
It could be that everyone here is telling the truth. Those launching these campaigns may simply be doing something they believe might win approval in the NDP, storing up favours owed from the next president of Egypt.
But if the opposition's analysis is accurate, what is still not clear is the position of President Mubarak himself.
Some years ago, Hosni Mubarak said he would serve Egypt to his last breath. He has made a point of not appointing a vice-president, and so there is no clear successor.
His attitude to his son's candidacy has never emerged publicly. Certainly Gamal has never been openly endorsed by his father.
Some believe that the president may have his doubts about his son's credentials.
Are those who are mounting these campaigns, then, challenging the president? Or is it a way of testing the waters?
Egyptians are used to their politics being conducted in a sometimes less-than-open manner.
But if this really is the beginning of a serious attempt to launch Gamal's candidacy, it shows a remarkable lack of self-confidence in the man who could be Egypt's next leader.