The former head of the United Nations' nuclear watchdog agency has repeatedly called for democratic reforms in his homeland and has made a point of not ruling out that he will challenge President Hosni Mubarak, who has held power under emergency laws since 1981.
Up to 1,000 ElBaradei supporters cheered him when he arrived Friday at Cairo International Airport after stepping down as head of the International Atomic Energy Agency in November after 12 years in the post.
They called on the 67-year-old diplomat, one of the best-known public figures in Egypt and with a growing popularity, to take on one of the world's longest running authoritarian regimes in next year's presidential elections.
ElBaradei has made his candidacy conditional only if an independent judicial review and international oversight of the election was guaranteed. He also called for the repeal of a 2005 constitutional amendment that effectively prohibits independent candidates from running for president.
So going after the top slot would be a risky enterprise in a country where human rights abuses abound and where political opposition is barely tolerated.
Egyptian authorities have been rounded up hundreds of members of the Muslim Brotherhood in recent months in advance of parliamentary elections. The Muslim Brotherhood is officially outlawed but has been allowed to put up candidates for parliament if they run as independents with no party machine behind them.
The prospect of ElBaradei, who won the Nobel Peace Prize in 2005 for his efforts to curb nuclear proliferation, clearly makes the regime uneasy.
The security services had warned his supporters to stay away from the airport when he returned home. ElBaradei was prevented from addressing those who defied the authorities by turning up.
The state-controlled press has vilified the former diplomat, who has no party organization to back him up but has come to be seen as a champion of the masses and what one European newspaper described as a "dissident leader-in-waiting."
Indeed, Al-Ahram, Egypt's leading newspaper and government-controlled, branded the swelling campaign behind ElBaradei as "tantamount to a constitutional coup."
It is widely believed that Mubarak, a former air force commander who has never designated a deputy, is grooming his son, Gamal, to succeed him. Mubarak is 81 and by all accounts is in poor health. He has not yet said whether he plans to run for a sixth term in 2011.
There is widespread opposition in Egypt to the emergence of a republican dynasty and growing resentment of the power elite who run the country. If the younger Mubarak, a business tycoon who in recent years has made a meteoric rise to the upper echelons of the ruling National Democratic Party, does inherit the presidency, he will follow the trail blazed by President Bashar Assad of Syria.
He became head of state after his father, Hafez, died in June 2000. His father, who had ruled Syria with an iron hand since 1970, had groomed him for the post.
Historically, dynastic politics was the preoccupation of monarchies but this spread to republican regimes as well in recent years in post-Soviet Central Asia and sub-Saharan Africa, most notably in Azerbaijan and the Democratic Republic of Congo.
In Yemen, President Ali Abdullah Saleh is seeking to do the same with his son Ahmed, who holds several key military commands.
Libya's leader, Col. Moammar Gadhafi, who has been in power since 1967, is expected to install one of his sons when he dies or steps down.
In all these countries, authoritarian rule has been established for decades, with little prospect in the foreseeable future of sweeping democratic changes propelling popularly elected figures to power.
In Egypt, as in other Arab states, the republican system has only been in place since the 1950s.
All of the Arab states, whether republics or monarchies like Saudi Arabia and Jordan, are to one degree or another police states where the democratic process, if it exists at all, is harnessed by the state.