Denis McDonough was chief of staff to President Barack Obama from 2013-2017. Kristie Canegallo was deputy chief of staff to President Barack Obama and oversaw health care policy and implementation, from 2014-2017. The opinions expressed in this commentary are solely theirs.

(CNN) President Barack Obama carried around with him a letter from Natoma Canfield , who struggled to get insurance to cover her cancer treatment. Her story was one of 130 million Americans with health conditions like diabetes, heart disease, autism, or suffering from addiction or diseases present from birth. The struggles of these Americans cast a glaring spotlight on the unfairness of our old health insurance system since, too often, their insurers charged them more or denied them coverage outright.

They and their struggles were the power behind finally passing comprehensive health reform, after a century of trying, in the form of the Affordable Care Act (ACA).

Ending discrimination against people with pre-existing conditions was not easy. It was why we took on the unpopular "individual mandate," pooling the costs of the sick and the healthy. It was why we ensured insurers cover key services like mental heath care and prescription drugs, even in the face of complaints that these requirements increased costs.

We can debate whether the system created by the ACA offers enough affordable choices, and last year President Obama put forward ideas for how that system could offer more. But we cannot debate whether people with pre-existing conditions have gained life-saving health coverage and whether their lives have been made better with the ACA's protections.

Their voices are being heard through the country and in the US Capitol right now, including proud advocates for the disabled community on Thursday . Major patient groups like the American Cancer Society's Action Network have stated their support for the current system -- along with their strong opposition to the bill that emerged in the Senate.

Senate Republicans claim that their bill protects people with pre-existing conditions: Insurers can neither charge them more nor deny them coverage. Yet, the text of the Senate bill shows that talking point is just not true The bill would undermine health care for people with pre-existing conditions in three different ways, rendering the "protection" virtually meaningless.

First, the bill's expanded state waiver authority would mean that people with pre-existing conditions, not insurers, could pay more for their coverage and care. The Senate bill would allow governors to waive essential health benefits, raise out-of-pocket cost limits, and break apart risk pools among other things. That would be possible with the stroke of a pen by a governor, with no legislative or even federal government approval required.

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With no individual mandate, reduced premium tax credits, no subsidies for lower and cost sharing, enrollment would plummet. Those who would remain covered would be those who need it most, driving up costs for the healthy.

To compensate, insurers would pressure states to waive essential health benefits or raise out-of-pocket cost limits, shedding benefits to avoid the sick and shifting costs to those who use it most. States could even allow issuers to design plans that indirectly segregate the healthy and sick, returning to the discrimination that caused so much suffering before. According to the Congressional Budget Office, one of the benefits likely to be excluded, leading to increased out-of-pocket spending by thousands of dollars, is mental health and substance abuse benefits , particularly disturbing at a time when an opioid epidemic is ravaging our country.

Second, the bill would allow a return to unlimited out-of-pocket costs and to annual and lifetime limits on coverage, including for those with health insurance through their employer. If a single state waives essential health benefits, any employer plan could use these diminished benefits as the basis for what it offers its enrollees.

For example, if a state excluded specialty drugs from essential health benefits, then any employer could impose an annual spending cap on such drugs or a lifetime limit for any enrollee, regardless of which state that enrollee is in. This would cause financial catastrophe -- or worse -- for parents of a child with leukemia or hemophilia.

Third, the health bill would end the expansion of Medicaid and, for the first time in history, cap federal spending on this coverage that millions of Americans depends. Medicaid cares for some of the most vulnerable among us, such as children with special needs, adults with severe mental illness and seniors who need home care.

The consequences of reduced Medicaid benefits or coverage for people with pre-existing conditions would be devastating, because they will need the same amount of care, but get less Medicaid support.

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These are only some of the effects of this bill that, on the whole, makes health care in America worse, not better. It raises health care costs, reduces coverage, weakens consumer protections and ends Medicaid as we know it -- and uses those savings to pay for tax breaks for the wealthy and corporations. No amount of tweaks or fixes before the final vote can address these fundamental flaws.

Everyone in America deserves a fair shot. This is why giving people with pre-existing conditions the same insurance, at the same cost, using the same doctors and hospitals, drove our efforts then. It is why it has bipartisan support now. And it is why the partisan, secretive drive to repeal the ACA, along with these critical protections, should end here.