House Democratic leaders sounded bullish Wednesday after launching an all-hands-on-deck effort to win support for a “robust” public insurance option in their health care bill.

“We think we have the votes now,” Democratic Caucus Chairman John Larson (Conn.) told reporters. “We have the votes to pass a robust public option.”

Larson cautioned that the details were still being worked out, and Democratic aides said Members were still being whipped at press time and did not release a tally.

Speaker Nancy Pelosi (D-Calif.) has asked her Members to line up behind the Medicare-based plan, rather than one that negotiates rates with providers, because it saves the most money, according to the Congressional Budget Office.

“The Members understand the choices that we have to make,” Pelosi said. “If you have one option that saves $110 billion and another that saves $25 billion, how do you make up the sum of that difference?”