It is Friday morning, and in a 14th-floor apartment in Falls Church, 3-year-old Omar is tearing around the living room, drawing on the walls, while his father, Radwan Ziadeh, is bent over his laptop, calling Syria.

The apartment overlooks the wide highway to Washington, and suburban America — McDonald’s, a church, a pool — is spread out below, but Ziadeh is oblivious to it as he takes calls and reads tweets and instant messages from his far-off homeland to piece together the day’s events.

“There are 15 people killed already today,” he says, “and we have heard nothing from Hama [Syria’s fourth-largest city] because all the electricity, telephones and Internet have been cut off.” After putting the numbers he considers reliable into his database of the death toll, he updates journalists and human rights groups.

Since the uprising in Syria began five months ago, and the regime of President Bashar al-Assad cracked down on communications as well as public protests, Ziadeh has gone from an obscure rights activist and academic to a full-time and prominent advocate for a vociferous opposition-in-exile. As part of a group in Washington that could play a key role in Syria’s future, Ziadeh dreams of returning to his homeland and forming a democratic political party. But he fiercely rejects comparisons with American-backed exiles such as Ahmed Chalabi, who returned to a political role in Iraq, the country he once fled.

Sen. Robert P. Casey Jr. (D-Pa.), who presides over Near Eastern affairs on the Foreign Relations Committee, has met several times with groups of dissidents, including Ziadeh. Like State Department officials, Casey is keen to see the exiles form a coherent opposition group that can function as an alternative government — not easy in a country where political activity has been effectively banned for more than four decades.

“We have got to provide them with as much support as possible,” the senator says. “There’s much work to do in preparing for the next phase.”

Assuming that phase is reached, Syrian activists in Washington could have a more direct impact on the course of Syrian events. They include Ammar Abdulhamid, who was a fiery Muslim religious leader in Los Angeles in the 1980s before becoming a secular, ponytailed rights campaigner today. Ahed al-Hindi, a confident student in his early 20s, says he was far closer to his American friends than the Syrian community until the uprisings began and he joined the campaign. Mohammad Abdullah works in technology, and his background as the son of a famous and often jailed political activist in Syria lends him credibility with the activists back home.

For now, they protest, campaign and brief lawmakers about the uprising that has left at least 2,200 dead. But in terms of political influence, it may be Ziadeh who has the most leverage. “He is not so much a person as an institution,” Abdulhamid says.

Ziadeh counts the dead, helps smuggle satellite phones into his homeland, publishes videos of protests and — because it is hard to reach people in the country — puts himself forward to explain Syria to everyone from Secretary of State Hillary Rodham Clinton to members of the U.N. Human Rights Council and politicians in Russia, Brazil and India.

“I spend every morning for three or four hours speaking to 30 to 35 people on the ground,” he says. “I never feel that I am out of Syria.”

As he speaks, Ziadeh receives an e-mail from someone who has escaped Hama, which has been retaken by government forces from protesters. The message says the electricity has been cut off for three days, the food is rotten and a man who left his house to buy bread for his children was shot dead in the street.

He talks to a Western journalist working undercover in Damascus to compare notes of reports, then puts on a tie and tears himself away from the computer. He has a meeting to get to at State, followed by one with the Canadian foreign minister and a television interview.

As he leaves, he murmurs an apology about the energetic Omar. “His father is sometimes not a good father,” he says. “I should have more time to play with him.”

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Born in the Syrian capital of Damascus, Ziadeh began writing about human rights in the 1990s, when the country was under the authoritarian rule of Hafez al-Assad, the current president’s father.

He set up the Damascus Center for Human Rights and remembers fondly the short period of openness called the Damascus Spring after Hafez’s son Bashar inherited power in 2000. Hundreds would gather to discuss freedom and democracy. But the new permissiveness disappeared fast, many were arrested and the debates went underground.

Ziadeh and his friends would go out of town, where they would be difficult to track down, and take the batteries out of their phones to avoid being bugged. “They were lovely gatherings, and we felt inspired to do something despite the danger,” he says.

But in 2007, threatened with arrest for his work, he fled to the United States, where he was a visiting scholar at Harvard and then George Washington University, from where he wrote books and articles calling for democracy in the Middle East. His voice, though passionate and scholarly, went largely unheard until he, like others, gained new relevance when the wave of revolutions known as the Arab Spring swept through the region.

He shows photographs of himself with Tawakul Karman, now a fierce female leader of uprisings in Yemen; Kamal Jendoubi, then an exile, who became the head of the Tunisian elections commission; and Bahi Hassan, a rights campaigner who recently declined a job in Egypt’s new post-Mubarak government.

Ziadeh, too, hopes to return home and participate in a real democracy in a free Syria although he doesn’t imagine himself as Syria’s next leader and is careful to stress the heroism of the protesters on the ground. “I do believe, I and my wife believe, that we’ll go back to Syria,” he says. “We never had a dream to stay out of Syria.”

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As he hastens between meetings, a diminutive figure perspiring in a suit on a sweltering day, he checks hundreds of messages on Facebook. Some are full of praise (one woman hopes to become his mother-in-law), but others are angry, suspicious of his ambitions. “Do you want to ride into the country on a French or Italian tank?” asks one. On a Web site called Ikhras — “shut up” in Arabic — he is described as an American-approved “democracy and human rights advocate” who does not represent the Syrian people or their aspirations. The writers rail at him for addressing the American Jewish Committee and mock his reedy voice and uninspiring speeches.

Such criticism is common. Some protesters in Syria express anger that the people representing their interests to the Obama administration, other governments and the United Nations are English speakers who live in the West and are not risking their lives at demonstrations.

“They say I am like Ahmed Chalabi,” says Ziadeh, referring to the Iraqi dissident whose political party received funding from the U.S. government and who lobbied hard for the removal of Saddam Hussein. “This is nonsense. I am not calling for military intervention . . . but, of course, people, when they want to discredit us, say this.” He says he receives no money from the government and instead relies on income from his writing and funds his travel with donations from the Syrian business community.

Even the State Department recognizes how counterproductive obvious American backing can be. P.J. Crowley, who until recently was Clinton’s spokesman, said State is keen to engage — with caution — with the diaspora, which has an influence on decision making.

“There’s the abject horror of what’s happening on the ground in Syria . . . but we’ve got to be very careful about choosing which people we support,” he says. Politics is about relationships, and it is difficult to build bonds when one group is on the streets in Syria and the other is in meetings in Washington, he says, so the opposition is an incoherent bunch at the moment.

At a recent gathering of the Syrian opposition in Turkey, the difficulty of unifying a group divided by distance, faith and ideology was clear as the group argued bitterly.

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At the end of the day, Ziadeh goes back to his place in Falls Church.

He lays out plates of traditional food — fried meat dumplings, little pastries called fatayeh.

The sky outside darkens. Ziadeh talks a little about his family, growing up in Damascus, the way it smells of jasmine ’round the ornate Azm palace in the old city. His mother is in hiding in Syria. The authorities will lift her travel ban only if she signs a paper condemning her son’s work, which she refuses to do. He would like to go back to visit her and see his two brothers — one of whom was arrested this week.

He speaks of the next step — testifying before the U.N. Human Rights Council — and more international travel to lobby countries such as Russia and Brazil to condemn Assad. Meanwhile, thousands of miles away, Syrian families bury the day’s dead.

Although he worked for this change for his whole adult life, it still seems unbelievable that a country in which dissent was crushed for so long has risen up.

“I never expected this day would come,” he says.