Vladimir Milov, a former deputy energy minister and now an adviser to Mr. Navalny, said the opposition leader’s team did not view ideology as an important factor in mobilizing protesters.

“The vast majority of people who come out are not partisans of any ideology or have specific views — they just want change in the country,” Mr. Milov said. “Most people who participate in protest movements are just tired of corruption.”

Mr. Navalny made a name as an anticorruption blogger in the early 2000s, but also engaged in nationalist politics, turning off many liberals. Three-quarters of the viewers of his “Navalny Live” YouTube channel were men, its director, Lyubov Sobol, told The New York Times last May. Ms. Sobol attributed that phenomenon to Mr. Navalny’s brusque, radical style.

Yet last weekend, about 45 percent of those at Mr. Navalny’s rally in Moscow were women, and 42 percent said they had never protested before this year, according to a group of sociologists who surveyed the crowd.