The question is whether Ms. Pelosi, whom Republicans have demonized in the past, would be an impediment to a revival.

“I think we need a new face,” said Representative Ed Perlmutter of Colorado. “There needs to be new energy injected.”

Other Democrats privately agree, but believe that Mr. Ryan is not the answer. Yet some of those who had been expected to compete to succeed her have left the House, notably Rahm Emanuel, now the mayor of Chicago, and Chris Van Hollen, who was just elected to the Senate from Maryland.

Ms. Pelosi has worked to respond to the criticism, meeting privately with Democrats and proposing minor changes to the leadership structure.

But the caucus has not fully recovered, and an increasingly new cadre of House Democrats are growing anxious.