The excitement increased when he unveiled the National Association for Change, a coalition of opposition movements pushing for democratic reform that hopes to break the regime's nearly 30-year grip on power.
Dr. ElBaradei, whom some see as Egypt's best opportunity for change, has injected fresh air into Egyptian politics at a pivotal time.
Egypt is bracing for its first political transition since President Hosni Mubarak took power in 1981. President Mubarak, now in his 80s, appears to be grooming his son Gamal to take power – possibly in the 2011 presidential election.
Current laws make it virtually impossible for ElBaradei to run for president, though he has hinted he would do so if those laws were changed. He has focused instead on advocating for reform of Egypt's political system.
But most of ElBaradei's support comes from the thin upper crust of Egyptian society. So now that the dust has settled, he and his coalition partners face the difficult task of trying to get ordinary Egyptians to join them in demanding democratic change.
'People don't care'
"When ElBaradei will be a real threat to the regime is when you ask someone on the street, 'Do you know ElBaradei?' And he says 'Yes, I love him,' " says Osama al-Ghazali Harb, leader of the opposition Democratic Front Party and a member of ElBaradei's coalition. "This is the core of the problem – that people don't care."
Indeed, less than one-quarter of Egyptians voted in the 2005 presidential election. Political rallies rarely attract more than a few thousand, and usually far fewer, in a nation of almost 80 million.
The price for political participation in Egypt is high – the regime regularly arrests, beats, and harasses activists – and that's part of what ElBaradei wants to change. He has called on the government to end the Emergency Law, which has been used to quell opposition for nearly three decades.
Under the law, expected to be renewed in May, gatherings of more than five people are illegal and security forces can detain people indefinitely without trial.
ElBaradei's camp also seeks constitutional reforms that will ensure independent monitoring of elections and make it easier for unaffiliated candidates to run for president.
ElBaradei supporters arrested
The bespectacled ElBaradei has been hitting Egypt's streets to get people to sign a petition for the reforms he has outlined. He has attended prayers at a historic mosque in Cairo, visited Coptic Christian leaders, rallied supporters in Egypt's Nile Delta region, and met with human rights activists.
Leaders of his coalition say they do not have a tally of signatures, but so far the petition appears to have fewer than the tens of thousands of signatures they had hoped would show broad popular backing. Online, however, ElBaradei has more than 200,000 fans on Facebook.
Ahmed Saleh, a leader of the Sixth of April youth movement, which supports ElBaradei, says people are too scared of government retaliation to join the campaign.
Indeed, the government has begun to crack down on ElBaradei's supporters – which may signal that the regime is beginning to feel some pressure from them.
While hundreds gathered at the airport to greet ElBaradei in February without a single riot policeman in sight, at an April 6 rally organized by Mr. Saleh's movement nearly 100 protesters were arrested and many were beaten.
In recent weeks the publisher of a book supporting ElBaradei was arrested, though he was later released, and another supporter was beaten and arrested.
"The government wants to make sure that everybody knows it's futile – you cannot protest against the regime. If you try to do this, you'll be beaten up; no matter if you're male or female, you'll be thrown into jail," says Saleh, who, along with other activists, is bitterly disappointed that the West has seemed to abandon Egypt's democratic activists.
Change to believe in?
There's a small possibility that Egypt will concede some of the constitutional reforms ElBaradei is calling for, says Mustapha Kamel al-Sayyid, a political science professor at the American University in Cairo. But in doing so, it may blunt ElBaradei's movement by co-opting his slogan of change.
Abdel Monem Said Aly, a member of the ruling National Democratic Party's Policies Secretariat, agrees that constitutional reform is needed, but says it must come from within the NDP, which is better equipped to tackle the issues that arise with reform. "The modern Egyptian state has always changed from within," he says. "Democracy happens in steps."
Professor Sayyid argues that the regime will not relinquish its grip on power – even if it means holding fraudulent elections.
The government would have a much harder time carrying out such a scenario, however, if ElBaradei musters widespread participation.
"If they confine themselves to getting signatures, I don't think they'll go very far," says Sayyid. "But one should not exclude that they might resort later on to mass action."
Even Mr. Harb, who supports ElBaradei's coalition, is cautious about how much he can accomplish. "Of course ElBaradei is a phenomenon," says Harb. "But don't expect that this will be some magical transformation."