Susan Boyce, married and the mother of four, doesn’t know when she will die, but she does know how. One day, her disease-decimated lungs will no longer be able to pump oxygen through her bloodstream.

“What happens with us is that we can’t get enough oxygen,” said Boyce, 54, of Rumson, N.J., who must take oxygen through a machine most of the day to breathe. “We die by suffocation. I don’t want to die by suffocation. It’s a slow, awful death.”

Which is why Boyce, whose condition causes her immune system to destroy healthy lung tissue, wants New Jersey to join the handful of states that allow physicians to prescribe lethal medications to dying patients.

New Jersey is one of at least 25 states considering aid-in-dying bills this year, according to the Denver-based advocacy group Compassion and Choices, and advocates think momentum is on their side.

Nearly 18 percent of Americans live in places where aid-in-dying is legal, and support is increasing: A recent Gallup poll found two-thirds in favor, up from half four years earlier. Some medical groups have softened their opposition. And increasing life spans, while generally a positive development, mean that more Americans are watching their parents die drawn-out, agonizing deaths.

Oregon voters legalized aid-in-dying — sometimes referred to as “death with dignity” or assisted suicide — by approving a ballot measure in 1994. Washington state voters followed suit in 2008, and a court ruling made it legal in Montana in 2009. Since 2013, Colorado, California, Vermont and the District have legalized it, either through ballot initiative or legislation. (The District’s law withstood an attempt last year to nullify it, but no patients have used it. Some advocates say the rules make doing so difficult.)

David Grube, who practiced family medicine in Oregon before retiring in 2012, once opposed aid-in-dying. But he said that as more states have legalized it and no evidence has emerged that patients are being pressured into the process, more people are becoming comfortable with the idea.

“It’s like same-sex marriage,” said Grube, who is the medical director of Compassion and Choices. “Forty or 50 years ago, I didn’t even know what a homosexual was. Now I see people in loving relationships, and that’s great.”

Even some critics of the aid-in-dying idea acknowledge the momentum.

“Many of my colleagues have softened,” said Ira Byock, a ­palliative-care doctor in Torrance, Calif., who is chief medical officer for the Institute for Human Caring. The institute provides medical, spiritual and emotional support to seriously ill patients and their families as part of the Providence St. Joseph Health system.

The American Medical Association remains firmly against aid-in-dying. “Physician-assisted suicide is fundamentally incompatible with the physician’s role as healer, would be difficult or impossible to control, and would pose serious societal risks,” the group says. Yet, 10 of its state chapters have dropped their opposition.

Officially, organizations such as the National Hospice and Palliative Care Organization maintain their opposition to aid-in-dying measures. But many individual practitioners have become more comfortable with the idea.

Many supporters credit as a turning point the extensive media coverage of the 2014 death of 29-year-old Brittany Maynard, who had an aggressive form of brain cancer and who promoted aid-in-dying before taking lethal medications prescribed by her doctor in Oregon.

“I really did believe that good palliative care could address the needs of people who were dying,” said Ann Jackson, the CEO of the Oregon Hospice Association from 1988 to 2008. But Jackson came to change her mind.

“The main thing I’ve learned is that that is not true,” said Jackson, who now consults on end-of-life issues. “We may be able to address pain and symptoms, but we cannot address the futility some people feel at the end of life, the suffering they feel over their loss of autonomy. Hospice care cannot allow people to control their lives if they are going to deny them the right to die at a time of their own choosing.”

The Catholic Church remains firmly opposed to aid-in-dying, as do many organizations that represent people with disabilities.

Oregon the model

Most state measures are modeled on Oregon’s law, which outlines steps for patients who want assistance in death: The person must be a state resident, at least 18 years old, still able to communicate, and diagnosed with a terminal illness with a prognosis of six months or less.

Patients must make two separate oral and one written request to their physician. The prescribing physician and a consulting physician must confirm the diagnosis and prognosis and determine whether the patient is capable of making a decision and isn’t impaired by a mental disorder. And the prescribing physician must inform the patient of feasible alternatives to medical aid-in-dying, including hospice care and pain control.

Oregon closely tracks how the law is used. Since the measure took effect in 1997, 1,967 people have received prescriptions under the law, and 1,275 have ingested the medication. Oregon data shows the median age for people who took this option in 2017 was 74.

Byock said he believes doctors who provide aid-in-dying are violating the most sacred stricture in medicine. He also believes that in most cases, it is possible to provide pain relief to dying patients and that the real problem is that quality palliative care is not universally available or embraced by the medical profession.

Byock also points out that the biggest concern of Oregon patients who used the law was not escape from pain, but their decreasing ability to enjoy their lives, loss of autonomy and loss of dignity, according to an Oregon report on its use. “Plenty of other people face those same conditions,” said Byock, including those with severe arthritis, depression or failing eyesight. “Once we go down this road, it’s a slippery slope.”

In Oregon, however, patients didn’t turn to aid-in-dying because they couldn’t get end-of-life services. About 90 percent were enrolled in hospice at the time of death, according to the most recent state data, published this year.

Byock acknowledges palliative care can’t always take away pain. It didn’t for T.J. Baudanza Jr., a onetime marketing manager who in 2015 died of colon cancer at age 32 in New Seabury, Mass. “T.J. died the way he feared he would,” said Amanda Baudanza, his widow, in an interview. “He suffered a prolonged, painful death because Massachusetts denied him the option of medical aid-in-dying.” He was in hospice in the last portion of his life.

T.J. had been a big supporter of an aid-in-dying referendum that narrowly missed passage in Massachusetts in 2012, not long after his diagnosis. Now Amanda is championing aid-in-dying in the state legislature.

“I’m Catholic, and so was T.J.,” Baudanza said, “but he and I both believed that God wouldn’t want anyone to suffer needlessly.”

In New Jersey, Susan Boyce says her lungs are doing well enough that she believes her death is still off in the distance. She doesn’t know whether she actually would take medicine that would end her life. But she knows one thing: “I want the option.”

Ollove is a reporter for Stateline, an initiative of the Pew Charitable Trusts.