After years of working to pass legislation that would give certain terminally ill patients the legal option to end their lives with a doctor’s prescription, state Sen. Jo Comerford is as optimistic as she’s ever been about the chances of a bill becoming law.

The bill, currently in the Senate Ways and Means Committee, would offer people more say in when and how they die.

“We’ve never been this close, and I’m really hoping that this is the session,” Comerford said last week.

Legislation (S 1331 / H 2246) from Comerford and Rep. Jim O’Day would allow mentally sound adults with a prognosis of six months or less left to live to “voluntarily make an oral request for medical aid in dying and a prescription for medication that the patient can choose to self-administer to bring about a peaceful death.”

When Rep. Kip Diggs first heard about the idea, he was against it. But Diggs spoke at a rally last week in support of the so-called medical aid in dying legislation and drew hearty applause from other supporters when he explained how O’Day helped to change his mind.

Meanwhile at the back of Nurses Hall at the State House, Pamela Daly and other advocates from Second Thoughts Massachusetts were holding signs and demonstrating against the controversial, long-discussed policy.

Diggs said that it took some reflection on his mother’s death from cancer and what it means to him to be a Christian, along with conversations with O’Day and Falmouth advocate Roger Kligler, to shift his position on the issue. The Cape Cod Democrat said supporting the bill is now “a no-brainer” for him.

Daly said she realized as she learned more about the proposal that it could be “extremely difficult and dangerous for many populations ... just marginalized people in general.”

“They have a very simple argument, those people. Easy, who’s going to disagree with them? Who wants to suffer?” she said after supporters talked about the pain of watching their loved ones suffer in their final days.

“We have a much harder argument.”

The issue of physician-assisted death has lingered around Beacon Hill for years, with advocates claiming steps of progress as the Massachusetts Medical Society voted to drop its longstanding opposition and instead adopt a position of neutral engagement, and then as aid-in-dying legislation got a favorable report from the Public Health Committee after at least five straight sessions of being sent to study.

This month, a new poll showed strong support for the idea among Bay State adults.

The University of Massachusetts Amherst/WCVB poll, released June 4, found that 44% of Bay Staters strongly support so-called physician-assisted death while another 23% said they somewhat support the idea. Eleven percent were somewhat or strongly opposed, and 22% said they neither support nor oppose it.

Massachusetts voters spoke directly to the issue in 2012, when they rejected a ballot question with 51% opposed and 49% in favor, a margin of 67,891 votes.

Comerford’s bill has cleared the Public Health Committee and the Health Care Financing Committee and is pending before the Senate Ways and Means Committee. Seventeen senators, close to a majority in that branch, are listed as co-sponsors. On the Ways and Means Committee though, only five members out of 17 are bill co-sponsors.

“Look how far we’ve come.,” said Sen. Su Moran. “All the concerns have been answered ... that’s all been incorporated. And we have something that, I think, the tires have been kicked on enough and it’s really ready to go.”

Moran is leaving the Senate after this session and called the aid-in-dying bill a “bucket list item” for herself.

But despite the talk of progress, none of the lawmakers who spoke at the rally last week offered a concrete timeline for next steps or even suggested that it could get a vote of either legislative branch before formal lawmaking ends July 31.

“We are becoming more and more confident that this will be the year that we get this bill across the finish line,” O’Day said at the start of his remarks.

He ended his remarks by saying, “If, for some reason, we stumble at the one-yard line, there’s another session right behind it. I’m not saying anything negative, just we cannot — we will not — give up the fight.”

But Daly and other opponents said they don’t sense the same kind of momentum for the legislation as supporters do.

She said the feedback she hears from lawmakers suggests there is little appetite among elected officials to wade into the touchy topic.

“I don’t think it’s as close as they seem to think it is. There are a lot of politicians who don’t like to speak about this bill because it’s so controversial ... and they feel that it’s such a big quagmire,” Daly said.

“It affects so many people in so many different ways. There’s a religious aspect, there’s a moral aspect. There’s Democrat or Republican, it touches everybody. So it’s a really hot-button issue … because it’s something so sensitive to so many people that, one word, and they could lose a whole bunch of constituents. But I don’t think it’s as close as they make it out to be.”

Opponents like Daly contend that authorizing the policy could expose patients to coercion and abuse. Disability advocacy groups warn of a slippery slope — arguing that authorizing assisted death for terminally ill patients is “just another incremental step to make non-terminal disabled people eligible for this as has happened in Canada and much of Europe,” said John Kelly of Second Thoughts Massachusetts.

Gazette Staff Writer Alexa Lewis contributed to this article.