South Dakota Voters Reject Measure That Could End Medicaid Expansion

South Dakota voters rejected a constitutional amendment that would have ended the state's Medicaid expansion automatically if the federal government's share of the cost dropped below 90%, according to unofficial results. About 56% of voters cast ballots against Amendment I, the Secretary of State's office reported late Tuesday.

The vote keeps intact the expansion South Dakotans approved in 2022 through Amendment D, which extended coverage to adults with incomes at or below 138% of the federal poverty level. Amendment I would not have repealed that coverage outright. It would have removed the constitutional requirement to maintain it if Washington reduced its matching rate — a conditional trigger written into the state's founding document.

Nothing in federal law currently puts that trigger at risk of firing. Under the Affordable Care Act, the federal government pays 90% of the cost of covering the expansion population, and that rate has not fallen.

The argument for the trigger

Supporters pitched Amendment I as taxpayer protection. If Congress ever cut the federal match, they argued, the state would be constitutionally obliged to make up the difference, forcing either a tax increase or reductions elsewhere in a state budget that funds roads, schools and prisons from the same pool.

That is the risk the amendment was designed to price. A state cannot easily walk away from an entitlement it has written into its constitution, and South Dakota's version is unusually rigid — the obligation sits above the Legislature, changeable only by another statewide vote.

The argument that won

Opponents put a number on the other side: roughly 30,000 South Dakotans whose coverage they said was at risk. They also argued that pulling expansion would hit hospitals, particularly rural ones that rely on Medicaid payments to cover uncompensated care in communities too small to support a stand-alone emergency department on private insurance alone.

The 56% margin suggests the second argument traveled further. Voters approved a citizenship requirement for voting and an unclaimed property trust fund in the same election, and rejected a separate proposal that would have raised the threshold for future constitutional amendments to 60%.

That last result is the one that matters for anyone thinking about the next health care ballot fight. Amendment L would have made it harder to amend the constitution by initiative — the exact route that produced expansion in 2022. South Dakotans kept the simple majority.

Why it matters beyond one state's coverage rolls

Medicaid is the single largest payer of mental health services in the United States and has taken on a growing share of substance use disorder treatment, according to the Centers for Medicare & Medicaid Services. That makes the program's enrollment rules a treatment access question, not only an insurance one: when expansion eligibility narrows, medication-assisted treatment, detox admissions and outpatient counseling financed through Medicaid narrow with it.

South Dakota's vote also lands against a federal backdrop that has been moving in the other direction. Work requirements, eligibility redeterminations and changes to how states define medically frail exemptions have been litigated and rewritten across the country this year, and several states have built their own triggers and sunset clauses into expansion statutes.

Amendment I was an attempt to write one of those triggers into a constitution. It failed by a margin wide enough that its sponsors are unlikely to read it as a rounding error.

What happens now

The expansion stays as written. Adults below the income cutoff remain eligible, the state remains constitutionally required to cover them, and the 90% federal match remains the assumption the budget is built on.

The open question is what happens if that match does change. Without the amendment, South Dakota would face the same choice every other expansion state faces: absorb the cost, restructure coverage, or go back to voters. Tuesday's result settles the mechanism — any future retreat would need a statewide campaign, not a quiet line in an appropriations bill.