Today, 40 states and the District of Columbia have taken advantage of the Affordable Care Act's move to open the program to able-bodied Americans with incomes below 138% of the federal poverty level. Even Republican-led states like North Carolina have buckled under the expansion wave. And there's mounting pressure for the 10 holdouts to follow suit.

A new paper from the Paragon Health Institute makes it clear that those 10 states should continue to resist. Medicaid expansion has wasted taxpayer dollars, drawn money away from other programs and patients in greater need, and left enrollees with worse coverage than they had before.

Medicaid was created as a safety net for the most impoverished Americans. Each state administers its own Medicaid program with the aid of federal dollars. For each dollar a state spends on Medicaid, the feds provide at least one additional dollar.

States with per-capita income below the national average receive more than one dollar for each dollar they spend on Medicaid. By statute, the federal government can fund no more than 83% of a state's Medicaid program.

To encourage states to expand Medicaid, Obamacare made the deal even sweeter. It promised to cover no less than 90% of the cost of Medicaid for the expansion population in perpetuity. Unsurprisingly, that got many states to bite.

In spite of that generous federal support, Medicaid expansion has given the states much more than they bargained for. As the authors of the Paragon paper, Brian Blase and Drew Gonshorowski, write, "States that have expanded their Medicaid programs typically have much higher enrollment and spending than projected."

All this new Medicaid spending by states has crowded out funding for other state imperatives like public education and infrastructure.

It's also been expensive. Blase and Gonshorowski estimate that expanding Medicaid in Florida could cost the state $176 billion from 2025-2034. After accounting for the federal contribution, Florida taxpayers would have a new $17 billion burden to shoulder on their own.

Worst of all, Medicaid expansion encourages states to focus on the more profitable—but less impoverished—expansion population at the expense of the program's legacy enrollees. One study found that expansion has siphoned resources away from children, the disabled, and elderly Medicaid enrollees.

To make matters worse, Medicaid expansion often leaves enrollees with worse coverage than they previously had. According to Blase and Gonshorowski, 65% of Floridians who would gain Medicaid coverage would be giving up "private coverage, which offers better access to both primary and specialty care appointments."

Medicaid beneficiaries often struggle to put their coverage to use. Because of the program's low reimbursement rates, doctors tend to limit the number of Medicaid patients they'll see. That leads to waits for care—waits that worsen when a surge of new able-bodied enrollees gain coverage.

And when Medicaid beneficiaries can't be seen in a timely fashion, they go to the emergency room—one of the highest-cost places to deliver care.

Perhaps we shouldn't be surprised, then, by research showing that Medicaid has little impact on patients' health. A landmark study of Medicaid expansion in Oregon in 2008 found that it "produced no statistically significant effects on physical health."

There's a final reason states are right to say "no" to Medicaid expansion—fraud. Improper payments by the program climbed from $36 billion in 2018 to $80 billion in 2022, thanks in large part to a COVID-era suspension of eligibility reviews. Federal taxpayers spent billions on coverage for people who aren't legally entitled to it. Expansion makes such fraud more likely.

Given the pressures on the program, states should be looking to restrain the growth of Medicaid. One way they can do so is by imposing work requirements as a condition of receiving benefits—with the goal of transitioning people off public coverage and onto private health insurance, whether through a job or through the exchanges.

The Biden administration has continued to press for Medicaid expansion in the 10 states that have thus far refused. But those states are right to hold fast. Agreeing to Medicaid expansion means agreeing to a wasteful, expensive program that fails to deliver for patients.

Sally C. Pipes is president, CEO, and the Thomas W. Smith fellow in healthcare policy at the Pacific Research Institute.