One spring morning in April, Susan Gottschall of St. Louis County got a glimpse of what the Affordable Care Act's Medicaid expansion program might look like if it is upheld next week by the Supreme Court.

Gottschall, 44, dropped by a city health clinic on the south side that morning to apply for the program, which has put Medicaid coverage within reach of thousands of once ineligible people.  Ordinarily, able-bodied adults are excluded from Medicaid in Missouri. But the pilot plan offers basic health care to anyone whose income is no more than 133 percent of the federal poverty level -- roughly $14,000 for a single person living alone.

The local program will last 18 months, until 2014, when the needy were scheduled to receive similar health benefits as part of ACA. Whether that happens depends on how the U.S. Supreme Court rules on arguments that the federal government is overstepping its bounds by, among other reforms, expanding Medicaid to cover millions more uninsured Americans.

The local Medicaid expansion program, called the Gateway to Better Health, offers some uninsured St. Louis and St. Louis County residents access to medical services at very low rates at city and county health clinics. The patient copays will range from 50 cents to $3 for doctor and dental visits and generic prescription drugs. Patients might expect to pay $15 for a clinic visit.

Coordinated by the St. Louis Regional Health Commission, the pilot is part of a demonstration grant to help the federal government and local providers determine the best and most effective way to serve Medicaid recipients. Under the old system, clinics got a block grant to serve their patients. Under this model, providers will be paid on the basis of services delivered, with emphasis on enhanced coordination, quality and efficiency in care.

This demonstration project, which begins July 1, will mark the second major shift in 15 years in the way the St. Louis region serves its medically needy. The first shift came in 1997 when St. Louis' last public hospital, Regional Medical Center, closed. With the shutdown, the area faced the potential loss of $25 million annually in federal funds for hospital-based care.

The federal government was persuaded to grant St. Louis a waiver, allowing the region to continue getting the federal dollars and shift to a beefed up clinic-based health system.  The region receives $25 million a year, and primary care is provided through a robust clinic system that keeps the needy from using emergency rooms for routine health care.

This transformation is mentioned in a study by George Washington University. Financed by the Commonwealth Fund, the report looks at ways that health care is being coordinated and integrated in six states. It praises the work of the St. Louis Regional Health Commission and the Integrated Health Network.

"Remarkably, despite Regional’s closure," the study said, "some components of the St. Louis health-care safety net have flourished over the past decade. In large measure, this is due to a set of strategic alliances that operate with a commitment to move the safety net beyond a contentious, fragmented history toward a more coordinated, higher-quality, better resourced future."

The study singles out Robert Fruend, head of the Regional Health Commission, as "a charismatic CEO who managed to engage the participation of key stakeholders across the safety net and the broader health care market."

It adds that the shutdown of Regional Medical Center "appears to have served as the catalyst for a spirit of collaboration and coordination in the St. Louis health-care market" and the creation of a "business plan to restructure the St. Louis safety net."

But even as the area's new community health model goes live on July 1, Fruend mentions the potentially adverse impact of the pending court decision on ACA. The expectation in 2014, he says, is that "the population that we are serving will be covered under expansion of Medicaid if that portion of the Affordable Care Act is held to be constitutional."

What if it isn't? Fruend responds: "We will have a $25 million gap from our program, and we'll have to put our thinking caps on and come up with a  new plan."

For now, however, he and others are focused on starting the new Medicaid coverage on July 1. Fruend expects about 30,000 people to be served, reaching about a fifth of uninsured residents in the city and county through a network of clinics -- St. Louis ConnectCare, Grace Hill Health Centers, Myrtle Hilliard Davis Health Centers, People's Health Centers, Family Care Health Centers and the St. Louis County Health Department.

"We're very excited to keep our program in place and pilot some new things for the country," Fruend says.

More than $60 million in federal and state funds have been put into the region's health-care safety net during the past two years, serving tens of thousands of people who otherwise would not have access to doctors.

Without primary care through clinics, Fruend says, "we'd expect to see about 50,000 emergency room visits next year in our urban core, and we just don't have the capacity for 50,000 additional visits."

To prod medical providers to accommodate the millions of new Medicaid enrollees under ACA in 2014, the federal government will raise reimbursement levels to those paid to doctors who treat Medicaid patients.

But the biggest incentive involves the federal government's decision to cover all of the cost for adding the new Medicaid enrollees during the first three years of ACA, from 2014 through 2017. After that, the federal government will begin reducing its share of Medicaid funding for the new enrollees to 90 percent by the year 2020 and beyond.

Even with the federal government picking up 90 percent of the cost, some of the 26 states suing the federal government over ACA worry that they will be unable to cover the remaining 10 percent of Medicaid costs after 2020. The Obama administration has argued that states will have time to figure out how they will cover their 10 percent share. States also fear the federal government might eventually require them to pay more than 10 percent of the cost.

Such issues don't seem to cross the minds of area residents like Gottschall, the piano teacher without health insurance who lacks the money to pay for it out of pocket. Instead, she was awed in April upon hearing that the program for which she signed up would offer continuity of care through a medical home and promises access to a doctor and prescription drugs for no more than $3 a visit.

She mentioned having gone without a mammogram, a pap smear and other services "because I can't afford them."

Eligibility for the new program means health insurance could be less of a worry during the next 18 months -- and perhaps beyond. But she knows it depends in part on a court ruling.