In the past year, much of the debate around the Affordable Care Act (ACA) has concerned Medicaid expansion, which the legislation’s authors specifically designed to make health care available to more low-income Americans. The ACA originally called for Medicaid expansion across the United States, with the federal government increasing the eligibility cap from 100 percent of the federal poverty level to 133 percent and increasing Medicaid disbursements to cover the added costs. Thanks to a vicious Supreme Court battle, however, states won the right to opt out of the expansion; to date, 23 states have refused it, costing themselves billions of dollars in federal funding.

The inequalities when it comes to accessing Medicaid—move to a different state and your health coverage and benefits eligibility could change radically—are, rightly, a subject of considerable concern. But the issue of provider availability is a pressing one too, and it’s been largely overlooked in discussions about the subject: What’s the point of having Medicaid if it isn’t even available? According to a report from the U.S. Department of Health and Human Services (HHS), more than half of surveyed Medicaid providers are, in reality, completely inaccessible. This presents an obvious problem for huge numbers of Americans—and it acts as yet another indicator that the social safety net is not functioning as it should be.

HHS researchers randomly selected 1,800 physicians that state agencies had listed as Medicaid managed care providers to determine whether they could make basic, non-urgent appointments with them, based on timeliness and availability. Thirty-five percent of providers had moved with no forwarding information, which isn’t much use to patients seeking doctors. Eight percent weren’t accepting new patients, while another eight percent said they didn’t participate in Medicaid at all. New patients entering the system in search of a doctor for the first time, in other words, would come up short, as would those who had recently relocated.

Even in cases where providers were actually available and willing to make appointments, the median wait time for new patients was two weeks, with many specialists having much longer wait times—a potentially significant issue for those with pressing medical concerns like cancers or seizures that need to be addressed as quickly as possible. Meanwhile, primary care providers were less likely to accept patients at all, making it difficult for people to enter into the health system so they could get referrals to specialists, if needed.

These findings have real and very serious implications for all Medicaid recipients in the United States, but especially for women, who are more likely to enroll in Medicaid than men. Those specialists with the extensive wait times, after all, include gynecologists, a primary point of care for low-income women who need a variety of reproductive health services including preventive care, access to birth control options, sexually transmitted infection testing and treatment, and referrals to obstetricians (another specialty provider) for prenatal care.

Women require a gender-specific health exam on an annual basis, according to the American Academy of Obstetricians and Gynecologists; those who receive intermittent care may encounter complications as a result of undiagnosed early stage cancers or worrying cellular changes. They can be at greater risk of untreated STIs and STI transmission, and their pregnancies may be identified later than they should be. This, in turn, can make it difficult to obtain vitally needed prenatal care for both mother and fetus: Doctors may not identify complications in pregnancy in a timely fashion, and abnormalities of fetal development may also remain undiagnosed.

Women are not the only ones whom this gap in services affects, of course. In most states, more than half of Medicaid beneficiaries are children; in some cases, especially in conservative regions, that statistic climbs closer to 75 percent. People of color make up half or more of Medicaid beneficiaries, particularly in red states.

In 1965, the government instituted Medicaid as a safety net for the United States’ poorest people. Fall below the poverty level, the program’s officials promised, and you’ll be eligible for this basic health-care coverage. Yet, even in the wake of the significant health-care reforms promised under Obamacare, Medicaid is failing. And that means that the United States is failing too, leaving its most vulnerable out in the cold.

People left out of the Medicaid expansion and caught in the coverage gap have no recourse when it comes to accessing health care, instead relying on public health clinics already stretched to capacity with patients who can only pay part of their bills, if that. For those who do have Medicaid, the half-and-half chance of accessing a physician has serious implications. If there’s no available provider in their area, they need to forgo treatment altogether or determine how they’re going to get to one working further away. Meanwhile, physicians listed as Medicaid providers who don’t update their listings or refuse to take on new patients aren’t being penalized for failing to fulfill their social and government contracts, and thus have no incentive to update their listings or change their policies.

To fix the problem, HHS’ report recommended working with states to update the accuracy of their provider listings, monitoring plans to determine whether they conform with government standards, and confirming that each state’s program actually meets the needs of the people enrolled in it. The Centers for Medicare and Medicaid Services has resolved to work with HHS to implement those recommendations, but for every day wasted, the government is failing patients who were promised something by the ACA and have yet to get it.

There are serious public health ramifications embedded in the failures of Medicaid. People who cannot seek medical treatment are more likely to develop costly complications, including exacerbations of existing illnesses, which cost states more in the long term when they show up at emergency rooms desperate for treatment. Meanwhile, people with untreated illnesses—the restaurant worker who handles lettuce, the retail clerk who doesn’t wash his hands—still show up for work and participate in society in order to retain their jobs and their limited income, becoming vectors for the transmission of germs.

In a broader sense, the inability to access health-care services cuts into Americans’ quality of life and their ability to pursue opportunities that might allow them to break the cycle of poverty. Adequate health-care services aren’t a luxury, but a basic human right, vitally necessary to benefit individuals who need services as a well as the population as a whole. To have a functioning nation, we need to have a healthy nation—and right now, that isn’t possible for large numbers of people.

And this problem is only going to get worse as the Medicaid “fee bump” ends. While the ACA originally raised compensation for Medicaid providers to encourage them to enroll in the program, that increase ended on December 31, leaving doctors earning less for their Medicaid patients. That creates a sort of reverse incentive, encouraging physicians to stop accepting new patients or to consider terminating Medicaid agreements altogether, at precisely the moment when more providers, not less, are desperately needed. The ones left holding the bag will be patients, who will have an increasingly difficult time locating providers.

Obamacare may have been a good start, but as the continued failures with Medicaid illustrate, it’s not the end of the line.