“This law is contrary to Shariah and must be stopped,” Mr. Abdel-Jalil told the crowd, vowing that the new government would adhere more faithfully to Shariah. The next day he reiterated the point to reporters at a news conference: “Shariah allows polygamy,” he said. Mr. Abdel-Jalil is known for his piety.

He also remarked cryptically, “We will not abolish any law.”

Still, some women here saw the collective remarks of the chairman of the Transitional National Council as a menacing sign that the new Libya would mean new repression. Human-rights lawyers also viewed the comments as a clearly aimed swipe at the Qaddafi law on marriage, as did a scholar of Islamic law at the University of Tripoli.

Libya experts abroad saw the leader’s foray as a political effort aimed at placating newly influential Islamists. “He and the other leaders are not quite certain which way this is going to turn,” said Dirk J. Vandewalle, an associate professor of government at Dartmouth College. “They are hedging their bets. The worrisome thing is he mentioned these things, which take him outside the mainstream.”

Abroad, the reaction was one of dismay among allies whose military firepower ensured Colonel Qaddafi’s fall. The French foreign minister, Alain Juppé, said: “This is a problem for us, especially in regard to respect for the dignity of women.” He later was forced to defend the government’s championing of Libya’s rebels against critics in the National Assembly.

And among young women at the university in Tripoli, the sentiment was overwhelmingly negative, even for those more tightly wrapped in head scarves than the others, who agreed with Mr. Abdel-Jalil that Shariah should be the basis for the country’s as-yet unwritten new constitution.