Story highlights The $800 billion reduction is confirmed to CNN by a senior administration official

What to do about Medicaid was a major flashpoint of the House GOP bill,

(CNN) Donald Trump's budget that is expected to be unveiled on Tuesday will include $800 billion in cuts to Medicaid -- a move that underscores the President's resolve to significantly downsize the federal program even as Republican lawmakers are clashing over the issue in Congress.

The $800 billion reduction, confirmed to CNN Sunday evening by a senior administration official, assumes that the GOP health care bill that the House passed earlier this month would become law, that official said.

The House legislation to dismantle the Affordable Care Act -- President Barack Obama's landmark health care law also known as Obamacare -- would significantly curtail federal support for Medicaid.

Under that bill, in 2020, states that expanded the program would no longer receive enhanced funding to cover low-income adults, while states that did not expand previously would not be able to do so, starting immediately. Some 11 million adults have gained coverage under Medicaid expansion.

Also, the bill would reduce federal funding for the entire Medicaid program, which covers more than 70 million low-income children, adults, disabled Americans and the elderly. States would either receive a set amount of funding per enrollee, known as a per capita grant, or fixed funding in the form of a block grant.

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