California's Legislature is advancing a proposal modeled after Oregon's law permitting patients diagnosed with six months or less to live to take lethal pills prescribed by their doctor.

The issue has stirred emotion from the Capitol to the pulpits, with supporters casting it as a matter of personal choice and opponents saying it is an immoral compromise of the sanctity of life and a doctors' oath to do no harm.

The two sides agree on this much: If California legalizes physician-assisted suicide, it will prompt many other states to follow suit and perhaps even prepare the way for a national law.

"That's what I certainly am hoping," says Patty Berg, a Democratic assemblywoman from Eureka in Northern California who is the leading sponsor of the bill. Berg says the bill goes next to the appropriations committee. She believes it will go to a House vote before the end of this month.

"Absolutely, other states would follow," says Anthony Adams, a Republican assemblyman from Hesperia and an opponent. An assisted-suicide law in California, he says, would project to the nation "the false illusion that this is somehow a credible thing to do."

In 1994 Oregon voters by a margin of 51% approved the Death with Dignity Act, which took effect in 1997. The U.S. Supreme Court upheld the law in a 2006 ruling.

Oregon's law, as well as California's proposal, permits doctors to prescribe a deadly dose for terminal patients who are deemed by a psychiatrist to be mentally capable and have been told they have six months or less to live. Similar proposals have failed in California's Legislature before, and bills failed in Vermont and Hawaii legislatures this year.

Since the law took effect in Oregon, 292 people have committed suicide under the law, according to a report last month by the state's Public Health Division. The division says 87% of the 46 people who took their lives in 2006 had cancer.

Opponents in Oregon say the law is not used as intended. They say some people are killing themselves for reasons other than pain and suffering and that the state has little or no oversight to monitor what's going on.

"The Oregon experience has been a real ticking time bomb," said Tim Rosales, spokesman for Californians Against Assisted Suicide, which is leading the effort to defeat the proposal.

Rosales cites statistics from the state that just less than half the suicide patients cited pain as their main motivation. Most, 96%, cited loss of autonomy and joy, and three-quarters cited loss of dignity.

"These are all clear indicators of depression — indicators for anyone to commit suicide," says Rosales, who argues those patients should have been treated for those problems, not given a poison pill.

Berg says the law is working as intended and is not misused.

"We should be allowed to live or die according to our own moral code," Berg says. "The opposition comes from a very small segment of society that believes it has a … better morality than the rest of us."

If California follows Oregon, the numbers of people using the law could be much larger.

Adams says the rate of suicide in Oregon, which has a population of 3 million people, could mean more than 500 people a year would commit legal suicide among California's population of 35 million.

That possibility has turned the initiative into a major battle between powerful players, splitting what normally have been allies.

This month, Cardinal Roger Mahony, whose Roman Catholic church strongly opposes the proposal, attacked the speaker of the state Assembly, Fabian Nunez, a Catholic supporter of the assisted-suicide proposal. During a Sunday Mass, Mahony called assisted suicide "against God's law" and said Catholics "should be troubled that Fabian Nunez … has allowed himself to get swept into this other direction, the culture of death."

The California Medical Association, which represents 35,000 doctors, opposes the measure because it is in direct conflict with a doctor's ethical duties. The California Association of Physician Groups, which represents more than 150 medical organizations, supports it.

The California Hospice and Palliative Care Association, whose members provide end-of-life care, opposes the bill on ethical grounds as well. But the American Academy of Hospice and Palliative Medicine has dropped its opposition for a policy of "studied neutrality."

California is closer than ever to making it legal, both sides say. Adams, who failed in efforts to stop the bill in a committee vote last month, says Nunez's support is "a signal to the rest of us that he has the votes" needed, 41, to push it through the Assembly.

California's Republican Gov. Arnold Schwarzenegger hasn't said whether he would sign the bill.

For Tom McDonald, 77, of Oroville in Northern California, the debate couldn't be more real.

The retired electronics worker learned in January 2006 that he has melanoma, the most serious form of skin cancer. He has outlasted his doctor's estimate that he had a year to live. But he says he watched his mother suffer a painful, six-month decline before her death, and he wants to avoid a similar end.

"How many times have we heard how friends and relatives have died in their sleep? That's wonderful. That's the way I want to go," he said.

Assisted-suicide supporters say McDonald should be able to choose how he dies. Opponents disagree.

"It is about giving doctors the legal right to prescribe medicine whose only purpose is to kill people. This is an immoral act, and it has no place being legislated," Adams says.

Wesley J. Smith, an author and activist against assisted suicide, says he thinks opponents can defeat the bill. Whichever way it goes, California's actions will be watched around the world.

"It's extremely important because California is such a big state, a bellwether," he says.