By Tami Luhby, CNN

(CNN) -- The House Democrats' divide over health care will be on full display Tuesday, when leaders plan to fulfill their midterm election promise by rolling out comprehensive legislation to strengthen the Affordable Care Act.

The bill aims to protect people with pre-existing conditions, as well as lower health care costs and reverse the Trump administration's moves to weaken Obamacare. House Speaker Nancy Pelosi, along with several committee chairs and freshman lawmakers, are set to unveil the legislation at a public event designed to mark the ninth anniversary of the signing of the landmark health care law.

What's not in the bill? Anything resembling a universal "Medicare for All" plan, a version of which was introduced by Reps. Pramila Jayapal of Washington and Debbie Dingell of Michigan last month and has more than 100 co-sponsors.

Pelosi acknowledged the goal of universal health care in a statement over the weekend, saying: "As we mark the 9th anniversary of the Affordable Care Act, we reaffirm our commitment to this fundamental truth: that health care must be a right, not a privilege, for all Americans."

But party leaders continue to slow walk the Medicare for All bill through the House. No hearings are scheduled, though the Rules and Budget committees have said they would hold hearings on the concept of so-called "single payer" programs, in which the federal government would have an expanded role in health care.

Jayapal's office didn't immediately return a request for comment.

House leaders are taking several steps to lower costs and shore up Obamacare, even as the landmark law comes under new legal threat from a lawsuit by Republican-led states. On Monday, the Trump administration dropped its previous support for elements of the law, instead siding with a lower court judge who ruled in December that the entire law should be invalidated in a case that may make its way to the Supreme Court.

Tuesday's House bill calls for increasing subsidies and allowing more middle class Americans to qualify. It would also provide additional funding for states to implement publicly-backed reinsurance programs, which reduce premiums by shielding insurance companies from high-cost enrollees.

The bill would also reverse the Trump administration's rules that make it easier for Americans to buy short-term policies that don't provide all of the protections required under the Affordable Care Act. Consumer advocates are concerned that these plans will draw healthy people out of the exchanges leaving sicker folks in the system -- which in turn would drive up premiums.

It would also curtail the administration's efforts to allow states to waive certain protections for those with pre-existing conditions, including weakening the standards for the benefits that insurers must provide, such as prescription drugs and maternity.

And the legislation would restore funding for enrollment assistance and outreach for the Affordable Care Act. The Trump administration slashed the budgets for advertising and sign-up aid, which many advocates say prompted fewer people to participate.

"The American people spoke loudly in November for exactly what this bill does," said Leslie Dach, a former Obama administration official and chair of Protect Our Care, an advocacy group seeking to strengthen the Affordable Care Act. "It's a giant step forward to providing lower-cost, better care and ending sabotage."