An emergency room entrance at a hospital in Santa Clarita, Calif. (Jason Redmond/Associated Press)

Abraham M. Nussbaum, chief education officer at Denver Health and an associate professor of psychiatry at the University of Colorado School of Medicine, is the author of “The Finest Traditions of My Calling: One Physician’s Search For The Renewal of Medicine.”

Over the past few weeks, there has been talk both of funding infrastructure projects and defunding Medicaid, at least in part. I recently saw a patient who reminded me that Medicaid itself provides an essential kind of infrastructure.

His black beard pointed stiffly down his chest. At the middle of his sternum, it flowered out into plastic beads, strung on the dozens of rosaries he wore about his neck. Red, yellow and green beads flashed as he yelled, “Go, go, go on, and get me out of here.”

A few years ago, before the expansion of Medicaid, we would have. We knew that if this patient stayed in the hospital, we could extinguish his mania and treat his acute injuries. We also knew that extended hospitalization was futile without access to ongoing care as an outpatient, so we often gave patients like him the green light for discharge.

He was homeless, mentally ill and uninsured. Back then, the last of those problems often seemed the most insurmountable.

So patients like this one cycled between the street, where acute ailments often became permanent disabilities, and the hospital, where they received expensive acute care without access to cost-effective primary care.

The Affordable Care Act, and our state’s acceptance of the Medicaid expansion, transformed the lives of people such as this patient. It also transformed hospitals like the one where I practice.

When I started working at Denver Health, an academic safety-net system in downtown Denver, most of the patients I met were uninsured, so routine care was not readily available outside of safety-net institutions.

Safety-net systems have long cared for the uninsured, the underinsured and the publicly insured, so they think of themselves as our nation’s essential hospitals. Denver Health is a western cousin of safety-net systems such as Atlanta’s Grady Health, where Rep. Tom Price (R-Ga.), Donald Trump’s choice to be secretary of health and human services, practiced orthopedic surgery. Safety-net systems such as Grady Health and Denver Health provide the care you rarely see advertised on a billboard or announced on a newspaper’s front page — services such as paramedic response, public health, trauma care and care for people with serious mental illnesses.

Before the Medicaid expansion, our bearded patient used all of those services. The paramedics transported him in crisis to our psychiatric unit. The public-health department treated his sexually transmitted infections, and the trauma surgeons stitched him up after accidents.

Before the expansion, Medicaid eligibility depended upon income, disability and family status. Rules varied by state, but childless adults such as this patient rarely qualified for services.

In the District and the 31 states that have accepted the ACA’S Medicaid expansion, patients like ours now qualify on income alone, and doctors like me can deliver the most powerful medical breakthrough possible for them: access to care.

In Colorado, the Medicaid expansion halved the number of uninsured. In Denver, 94 percent of residents are now insured. At Denver Health, half our patients now receive Medicaid, which has enabled us to add physicians, integrate behavioral health into primary care, provide care in cost-effective outpatient settings and add quality jobs. Even though many private practitioners and hospitals refuse to accept Medicaid because of low reimbursement rates, safety-net systems stretched these modest payments into a network of essential services.

In the 19 states that have not expanded Medicaid, the situation is different, creating a health insurance coverage gap for 2.6 million Americans. A recent report by the Kaiser Family Foundation observed that childless adults account for more than three-fourths of that uninsured population.

When our patient was first hospitalized after the Medicaid expansion, his beard had turned gray. He was in his late 30s but looked so many decades older that we doubted his identity. We no longer doubted our ability to get him care. We could not only calm his mania, we could also get him appointments with an internist, podiatrist and psychiatrist, as well as a case manager and a job counselor. We could send him to care instead of the streets.

For now, the Medicaid expansion is intact and, with it, an essential infrastructure. So when we last discharged him, clean-shaven and looking his own age, our patient took off the rosaries. He needed only one now, so he distributed the remaining rosaries to thank his caregivers. In a way, I think he was passing out those rosaries to thank all Americans who support his access to essential care.