A day after she began a full whip effort for a health care bill with a robust public option, House Speaker Nancy Pelosi continues discussions with members in the hopes of reaching consensus before Thanksgiving.

"We will have a bill that will go to the floor and it will have a public option in it...the question is what form will that take," Pelosi said during her weekly press conference today.

Pelosi continues to use a steady stream of preliminary CBO numbers to convince squeamish members that a robust public option is a big money saver, and the most fiscally responsible way forward.

"Originally we were operating under a trillion dollars.... the president said a number around $900 billion. So that changed some of our discussions," Pelosi explained.

For example, the robust public option--that's how that has emerged because that takes you down $110 billion, and that's very significant when you're trying to go from just under a trillion to just under $900 billion. The negotiated rates, which has some support in our caucus, is over $900 billion.... Trying to give every option its fair shake, I have asked the CBO how do you get negotiated rates down under $900 billion. Some of the options are not palatable to members like putting significant numbers of people on Medicaid rather than into the exchange.

According to Pelosi's spokesman Nadeam Elshami, leadership expects to get more numbers today. The explanation sheds some light on the method the Speaker is using to gin up sufficient support for a robust public option: arguing, essentially, that without a robust public option, the bills costs increase, and the other cuts and changes needed to get the bill below $900 billion are significantly more controversial.

Like a number of key Democrats, Pelosi took a moment to herald the non-public option aspects of the bill, calling it historic, and confirming that the legislation will end the health insurance industry's exemption from anti-trust laws. (In the past, she has suggested that the absence of a public option would call the entire reform project into question.)

After the conference, Elshami pushed back on a critique being leveled by some Senate aides that the administration isn't showing leadership on the public option, and is therefore imperiling its chances. "I think the president has made his position clearly known about the public option that would provide the best competition," Elshami said. "The president stood before Congress before the nation and said his position on the public option."