Ten months after a broad popular uprising overthrew President Hosni Mubarak, the Salafis’ new brand of religious populism has propelled Al Nour and its allies to claim more than a quarter of the vote in the first round of parliamentary elections, surprising even the most seasoned Egyptian analysts and Western diplomats. The Salafis have outpaced the liberals to emerge as the principal rival — or potential partner — of the Muslim Brotherhood, the mainstream Islamist group whose party won 40 percent of the vote and is positioned to lead Parliament.

In the aftermath of the vote, Egyptian liberals, Israelis and some Western officials have raised alarms that the revolution may unfold as a slow-motion version of the 1979 overthrow of the shah of Iran: a popular uprising that ushered in a conservative theocracy. With two rounds of voting to go, Egypt’s military rulers have already sought to use the specter of a Salafi takeover to justify extending their power over the drafting of a new constitution. And at least a few liberals say they might prefer military rule to a hard-line Islamist government. “I would take the side of the military council,” said Badri Farghali, a leftist who last week won a runoff against a Salafi in Port Said, northeast of Cairo.

A closer examination of the Salafi campaigns, however, suggests their appeal may have as much to do with anger at the Egyptian elite as with a specific religious agenda. The Salafis are a loose coalition of sheiks, not an organized party with a coherent platform, and Salafi candidates all campaign to apply Islamic law as the Prophet Muhammad did, but they also differ considerably over what that means. Some seek within a few years to carry out punishments like cutting off the hands of thieves, while others say that step should wait for the day when they have redistributed the nation’s wealth so that no Egyptian lacks food or housing.

But alone among the major parties here, the Salafi candidates have embraced the powerful strain of populism that helped rally the public against the crony capitalism of the Mubarak era and seems at times to echo — like the phrase “silent majority” — right-wing movements in the United States and Europe.

“We are talking about the politics of resentment, and it is something that right-wing parties do everywhere,” said Shadi Hamid, director of research at the Brookings Doha Center in Qatar. They have thrived, he said, off the gap between most Egyptians and the elite — including the leadership of the Muslim Brotherhood — both in lifestyle and outlook.