States must take or leave the entire Medicaid expansion under President Obama’s healthcare law, and cannot expand the program only partially, the Obama administration said Monday.

The Health and Human Services Department (HHS) said the law does not allow for a partial expansion — at least not with the level of federal funding available to states that participate in the expansion.

The Affordable Care Act expands Medicaid to cover people at or below 133 percent of the federal poverty line. The federal government initially pays the entire cost of the expansion, with the federal share dropping to 90 percent by 2020.

Some states had asked whether they could expand Medicaid only partially — not all the way to 133 percent of poverty — and still get the full federal payment. HHS said Monday that it simply doesn’t have that authority.