About 40 percent of nonelderly, non-disabled adults who have Medicaid coverage aren’t working, according to an analysis from the Kaiser Family Foundation. But many of them are either in school or staying home to care for a family member, while about a third are too sick to work. Just 6 percent say they want to work but can’t find a job.

CMS declined to say how many people could be potentially impacted by the work requirements, saying it would depend how states designed the programs.

The requirements will likely be subject to court challenges.

Conservatives have long argued that social programs can be a disincentive to work and favor making safety net benefits contingent on working. In 1996, a welfare reform bill passed by the Republican-controlled congress and signed by President Bill Clinton, a Democrat, added work requirements to welfare benefits, among other changes to the welfare program now known as Temporary Assistance to Needy Families.

Alternative Lifestyle?

Medicaid, unlike cash welfare payments, isn’t a disincentive to work, because it doesn’t provide people with funds they’d need to pay rent or buy food, said Jeff Grogger, an urban policy professor at the University of Chicago. He said it’s not clear what problem a Medicaid work requirement would solve, and that there are better ways to help people find jobs or reduce the number of people receiving Medicaid.

“It’s not like Medicaid is providing some kind of alternative lifestyle that’s attractive and keeps people out of the workforce,” he said. “If we had fewer sick people and fewer poor people, that’d lower the Medicaid rolls. Thinking in those terms is more productive.”

Medicaid was historically a benefit that went hand-in-hand with welfare for the disabled and low-income single mothers and their children. In the 1980s and ’90s many states expanded eligibility to pregnant women, regardless of income or marital status. The ACA allowed states to expand eligibility to low-income adults without children, with the federal government covering most of the cost.

The successive expansions have turned the program into the largest source of health insurance for Americans. About 72 million people, more than one-fifth of the American population, had Medicaid coverage in 2017, according to CMS. About 39 percent of them are children, and another 23 percent are blind or disabled. The remaining adults, about 28 million people, include 12 million who became eligible for Medicaid under the ACA.

States would have to build new systems to determine who is subject to work requirements and verify whether beneficiaries fulfilled them, said LaDonna Pavetti, vice president at the Center on Budget and Policy Priorities, a left-leaning think tank.