AUGUSTA — The concept of allowing terminally ill patients to end their own lives under a doctor’s supervision hit a roadblock Monday when the Senate voted 18-17 against it.

The bill, LD 1270, would allow physician-assisted suicide in Maine but only with a range of caveats, including that the patient has to take lethal drugs by his or her own hand after significant counseling from health care professionals.

Maine’s proposal, modeled after a law in Vermont, would apply to adults who are terminally ill and who have a limited life expectancy. It includes legal protections for physicians, health care facilities and insurance companies.

“The premise of this legislation is very simple,” said Sen. Roger Katz, R-Augusta, who sponsored the bill. “A competent adult ought to have control over his or her own life, generally free from interference by the government. These libertarian ideas are ingrained in our society and in our law. It’s about dignity, it’s about self-determination and it’s about the right to choose one’s own path in life.”

Sen. Geoff Gratwick, D-Bangor, who is a physician, agreed with Katz.

The final question of life and death must be focused on what the patient wants after due deliberation,” Gratwick said Monday during debate in the Senate. “The health care provider must be very careful, very thoughtful and always respect the wishes of the patient.”

Sen. Andre Cushing, R-Hampden, said it’s wrong for anyone to choose to end his or her own life.

“I just think it is a horrific idea to have to make the choice to end someone’s life,” said Cushing. “I don’t believe Maine is ready for this. There are choices available.”

Sen. Amy Volk, R-Scarborough, was among the bill’s other opponents.

“I don’t believe that any one of us knows when life begins or when life should end, including ourselves,” she said.

During public hearing testimony on the bill in May, dozens of families and individuals told emotional stories about loved ones who suffered, in their opinions needlessly, during their end days of battling terminal diseases. There was also testimony from numerous people and organizations who object to it on moral or religious grounds.

The Legislature’s Health and Human Services Committee previously voted 7-6 against the bill.

The bill faces more votes in the House and Senate in coming days.