When the Affordable Care Act passed and the opportunity to buy health insurance arose, Michele Evans, 57, and her husband jumped at the chance. Together they own and operate their own business in Bozeman, Montana. But after Evans’ nearly 10-year battle with Lyme disease racked up more than $50,000 in uncovered medical costs, they learned the consequences of being uninsured. On Dec. 27, 2014, with the help of government subsidies, they paid their first monthly premium, and by this January, they officially had health care coverage. But now, Evans and her husband face a new risk: the potential invalidation of the very subsidies that made this insurance affordable in the first place.

In the latest challenge to the Affordable Care Act, the case known as King v. Burwell, Supreme Court justices are expected to issue a decision in late June about whether federal subsidies to residents of states that don’t run their own health care exchanges, such as Montana, are legal. If the court rules that these subsidies are not legal, up to 8 million people could lose their health insurance. For Evans and others who have experienced life without it, the prospect of not having insurance once again is daunting.

Today, the Evanses pay $81.76 per month for health insurance, Michele Evans said, thanks to a generous subsidy of about $859 per month. Evans was part of an amicus brief filed by the Service Employees International Union in support of the government in King v. Burwell, and said that if the court rules against the government, “we’ll lose it again,” Evans said. “We can’t really afford regular health insurance right now.”

In 2006, Evans was misdiagnosed by a doctor, she said, and for the next three years she struggled with Lyme disease, which can be debilitating if untreated. “I just sort of crashed and burned,” she said. Finally, in 2009, she began seeing a specialist for Lyme disease. Before that, she and her husband paid $400 every month for health insurance they barely used. But when she got Lyme, they decided to cancel the coverage and put the $400 toward paying out of pocket for visits to the specialist, blood work and antibiotics, Evans said. Finally, in 2011, she stopped working. “I was so sick. I really wasn’t functioning well at all,” she said. Eventually her husband stopped working too, to take care of her. “That was like the bleakest year of our life,” she said.

By now, Evans has figured out how to manage her Lyme disease effectively, but she said that having health insurance is crucial for them for other reasons. In the Montana winters, they often commute to work by snowmobile and snowshoe, Evans said. She doesn’t dwell on the prospect, she said, but “just a slip and a fall could be very detrimental for our finances because we’re in this precarious place of trying to pay off all this credit card debt.”

If the Supreme Court strikes down subsidies to residents of the 37 states -- including Montana -- that have federally run exchanges, Evans would have to drop health care. “I would be uninsured immediately,” she said. “That’s like a whole mortgage payment again.” 

In 2010, when the Affordable Care Act was passed, states had the option of setting up their own health care exchanges, or marketplaces, where people could shop for insurance plans, or handing over the task, in full or in part, to the federal government. And those who purchased insurance on those exchanges and qualified financially could receive subsidies from the government to help offset the cost.

Thirty-seven states chose to use the federal exchange, HealthCare.gov. But the challengers in the latest Supreme Court case, for which both sides presented oral arguments Wednesday, contest that four words buried deep in the law, “established by the state,” mean that subsidies can only go to people who bought insurance on exchanges run by the state, not by the federal government.

The Department of Health and Human Services has estimated that 87 percent of people buying health care in those 37 states, or nearly 6.5 million people, qualify for subsidies in the form of tax credits. If a Supreme Court decision strikes down these subsidies, the number of uninsured would jump by 8.2 million, the Urban Institute has estimated, and relief for premiums would end for 9.3 million people. The number of people who bought insurance on those exchanges would drop by 69 percent, it predicted.

For many, these subsidies are precisely what make health care affordable. “If the subsidies are taken away … it’s going to have potentially a tremendous impact on day-to-day lives” of Americans, said Kirsten Mayer, a partner at the law firm Ropes and Gray, which filed an amicus brief in King v. Burwell in favor of the government. For people with serious medical conditions, such as those who are living with HIV, taking away insurance can literally be a “life or death” matter, Mayer said.

Mary Rouvelas, senior counsel at the American Cancer Society Cancer Action Network, who filed another amicus brief for the network in favor of the government, pointed out, “There’s a very, very strong link between health insurance status and health outcomes.” With certain cancers, including breast and cervical, a patient has a much higher chance of surviving if the cancer is caught in the early stages; the uninsured are four times as likely as those with health care coverage to die of Stage IV (late-stage) breast cancer, Rouvelas stated. “Health insurance saves lives, and if people can’t afford it, there’s a huge human cost to having health insurance,” she said.

For Claudette Newsome, 42, a single mother in Houston, health insurance means everything. Having already lost a husband to cancer and a son to a bicycle accident, she is all that her 10-year-old and 14-year-old daughters have left. “I can’t get sick,” she said. “I’m the one that cooks their meals. I’m the one that they talk to. I have to stay healthy.”

“Having a subsidy definitely allowed me to have health insurance,” Newsome, a full-time student and a consultant who was part of the same amicus brief as Evans, said. “If those subsidies are taken away, we no longer have insurance,” she said. Newsome first bought health insurance via the Affordable Care Act in 2014, signing up in January for $184-per-month coverage that started in February. Before that, her children were covered through the governmental Children’s Health Insurance Program, but she had no insurance, a status that once led to her being removed from a hospital bed after a bad car accident, she says. She lost her husband to cancer five years ago, and though as a veteran he received care through the Department of Veterans’ Affairs, she wonders if he could have lived longer with different care. Now that she has a health plan, she can research doctors and pick the best one for her daughters to see, and “I can get my mammograms every year, like a woman is supposed to,” she said.

But if the Supreme Court rules against subsidies to states such as Texas, or Montana, “I would lose my insurance and I would go back to the old-fashioned way of doing things,” Newsome said, like searching online for home remedies. She said her daughters would go back on CHIP and would probably be forced to stop seeing the doctor Newsome prefers. She would then have to resort to researching her symptoms online, trying to narrow down what was ailing her, and go to a drugstore and try to treat herself that way. “I’m not a doctor,” she said, “I can’t rely on the Internet to diagnose me.”

“We need this insurance. We need that credit,” Newsome said, adding that she spoke not just of herself but of single parents everywhere. “We need that subsidy.”