Speaker Nancy Pelosi (D-Calif.) has started making her final argument for a robust public insurance option in a health care overhaul, framing the debate over the provision as a fight between insurance companies and the middle class.

Pelosi pressed her case to reporters on Thursday, arguing middle class Americans facing a new requirement to buy insurance also need a public insurance option to protect against insurance companies that have denied them quality coverage in the past.

“If we’re going to mandate that people must buy insurance, why would you throw them into the lion’s den of the insurance industry without some leverage?— Pelosi said.

She pointed to public opinion polls showing strong support for a public option even in the face of insurance industry critiques. And she signaled the House package could include more bad news for the industry. She said lawmakers are examining a $40 billion flat fee on insurers that’s under consideration in the Senate, indicated there is “tremendous interest— among House Democrats in revoking the industry’s anti-trust exemption, and highlighted a House provision requiring insurers plow at least 85 percent of premiums into providing coverage.

Pelosi still faces opposition from moderates to a version of the public plan pegged to Medicare reimbursement rates. But she indicated hewing closely to that approach will be key to preserving the public insurance option in future conference committee negotiations with the Senate. “I want to send our conferees to the table with the most muscle for America’s middle class,— she said.

Pelosi said a decision on the final shape of the provision is coming “in the next few days.—