Some conservative Senate Republicans, led by Utah Sen. Mike Lee, are considering significant cuts to Medicaid that would cause millions of people to lose coverage, the Wall Street Journal reported Sunday.

The aggressive cuts would ultimately provide states with less federal Medicaid dollars and shift costs typically covered by Medicaid away from the program, and onto hospitals and states. Conservative lawmakers also hope to give states more flexibility in how they allocate these federal funds and create incentives for spending Medicaid dollars more prudently.

During his presidency, Obama enhanced Medicaid under the Affordable Care Act (ACA) to expand coverage for more people. The American Health Care Act (AHCA) that recently passed in the House would allow the 31 states and D.C. that adopted these expansions to continue with the program as long as they sign up before 2020. However, after 2020, anyone who signs up would no longer benefit from the federal funds provided by the Affordable Care Act, reducing the 73 million low-income and disabled people in the United States who now benefit from Medicaid by 14 million, according to estimates from the Congressional Budget Office (CBO).

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In the House, many conservative lawmakers advocated ending Medicaid expansion before 2020 but were opposed by centrists.

In the Senate, cuts to Medicaid in the new health care bill may face a similar fate, since centrist GOP senators are concerned that the 2020 end date for federal funding to new Medicaid enrollees would leave too many of their constituents without coverage. Currently, 20 Senate Republicans represent states within the 31 that chose to expand Medicaid under the ACA. With this, moderate Republicans support a more gradual phase out of Medicaid expansions.

"I couldn't support the House bill, because I didn't believe it provided adequate coverage for people who are currently being helped by expanded Medicaid," Sen. Rob Portman, R-Ohio, told The Journal.

The bill currently forecasts an $839 billion cut to Medicaid over the next 10 years, according to the CBO. However, more conservative GOP senators are pushing for a more aggressive timeline to scale back on Medicaid.

Some Republican governors, like Ohio Gov. John Kasich, have voiced concerns about the potential cuts to Medicaid and are pressuring senators to avoid the change without a backup plan for those losing coverage. Other governors in some states that chose not expand Medicaid seek to reduce enrollment by imposing more requirements, like drug-testing, benefit time limits and work requirements.