LANSING, Mich. — For nearly a decade, Jack Kevorkian waged a defiant campaign to help other people kill themselves. The retired pathologist left bodies at hospital emergency rooms and motels and videotaped a death that was broadcast on CBS’s “60 Minutes.” His actions prompted battles over assisted suicide in many states. But as he prepares to leave prison June 1 after serving more than eight years of a 10- to 25-year sentence in the death of a Michigan man, Kevorkian will find that there’s still only one state that has a law allowing physician-assisted suicide — Oregon.

Experts say that’s because abortion opponents, Catholic leaders, advocates for the disabled, and often doctors have fought the efforts of other states to follow the lead of Oregon, where the law took effect in late 1997.

Opponents defeated a measure in Vermont this year and are fighting similar efforts in California. Bills have failed in recent years in Hawaii, Wisconsin, and Washington state, and ballot measures were defeated earlier by voters in Washington, California, Michigan, and Maine.

Kevorkian’s release could spur another round of efforts, if only to prevent anyone else from following his example.

“One of the driving forces of the [Oregon] law was to prevent the Jack Kevorkians from happening,” said Kate Davenport, a communications specialist at the Death with Dignity National Center in Portland, Ore., which defended Oregon’s law against challenges.

“It wasn’t well regulated or sane,” she said. “There were just too many potential pitfalls.”

Kevorkian, 79, was criticized even by assisted suicide supporters because of his unconventional practices.

He used a machine he’d invented to administer fatal drugs and dropped off bodies at hospital emergency rooms or coroner’s offices, or left them to be discovered in the motel rooms where he often met those who wanted his help.

At the time, some doctors didn’t want to give dying patients too much pain medication, fearing they’d be accused of hastening death.

Oregon law allows only terminally ill, mentally competent adults who can self-administer the medication to ask a physician to prescribe life-ending drugs, and they must make that request once in writing and twice orally.

Oregon’s experience shows that only a tiny percentage of people will ever choose to quicken their death, said Sidney Wanzer, a retired Massachusetts doctor who has been a leader in the right-to-die movement.

From the time the law took effect in 1997 until the end of last year, 292 people asked their doctors to prescribe the drugs they would need to end their lives, an average of just over 30 a year. Most of the 46 people who used the process last year had cancer, and their median age was 74, according to a state report.

Experts say the attention on assisted suicide has helped raise awareness caring for the terminally ill.

“End-of-life care has increased dramatically” in Oregon with more hospice referrals and better pain management, says Valerie Vollmar, a professor at Oregon’s Willamette University College of Law who writes extensively on physician-assisted death.

Kevorkian has promised he’ll never again advise or counsel anyone about assisted suicide once he’s out of prison. But his attorney, Mayer Morganroth, said Kevorkian isn’t going to stop pushing for more laws allowing it.

The state wants to go after money that Kevorkian makes following his release to help cover the cost of his incarceration.