The House’s bill would allow private insurers to charge people more as they grow older, and permit plans in certain states to cover fewer services. It also would have made exchange coverage more expensive and less comprehensive on average for low-income, sick, and older people. It would likely reduce coverage for pregnant women and people with mental-health issues as well. The last Congressional Budget Office score found that many of the 23 million fewer people who would be covered were drawn from those groups, as well as many of those who would keep coverage but suffer dramatic increases in premiums.

The Senate bill would alleviate some of these issues with slightly more generous credits for the poor, but would keep those central disruptions intact, and would leave more middle-class people without affordable coverage. It also allows even less generous plans to stand as benchmarks for exchange and employer coverage, which could likewise contribute to disruptions and deductible increases.

In recognition of the disruptions to the state-level exchanges through which individuals purchase coverage, the House bill set up a “Patient and State Stability Fund,” which would inject over $100 billion into state high-risk pools and reinsurance funds. The Senate largely replicates this approach with slightly less funding, although it does add an additional $2 billion fund for fighting the opioid crisis in 2018.

The much more drastic changes in the Senate bill as compared to the House bill come in the realm of Medicaid. The House bill immediately ended enhanced funding for the Medicaid expansion to able-bodied low-income adults under the ACA, while the Senate bill would slowly phase that funding out. This, in theory, would put millions fewer people immediately in the ranks of the uninsured and increase government spending over the House plan. But seven states (Arkansas, Illinois, Indiana, Michigan, New Hampshire, New Mexico, and Washington) have “trigger laws” that would immediately void their Medicaid expansions with any change in federal support, and it’s likely more states would choose to shutter their expansions well before the end of the enhanced funding window in the face of rising costs.

The House’s plan also restructured the open-ended funding of Medicaid to a per-capita cap scheme, where states receive a capped amount of funding each year per enrollee, and could choose to receive the funding up front in block grants. That Medicaid restructuring increased yearly funding by the medical Consumer Price Index plus 1 percent, a measure designed to keep per-capita caps roughly in line with inflation in the industry, but one that would also underfund Medicaid over time, leading to a growing gap between the number of patients who would be eligible under current guidelines, and the funds available to pay for their care.