The push to allow territories the right to legalise euthanasia has foundered in the Senate, with a majority of the chamber voting against the proposal before it reached the committee stage.

The proposal appeared doomed when senators Brian Burston and Peter Georgiou reversed their position on the legislation, switching from yes votes to no votes.

As recently as Tuesday the bill’s architect, David Leyonhjelm, was confident it would win the 39 votes necessary to pass the Senate, but the push fizzled out.

After the bill was denied a second reading, the Liberal senator Eric Abetz declared the “clear vote in the Senate will settle this matter for a generation”.

The Australian Christian Lobby also welcomed the result. “The inherent value of every life must continue to be maintained,” said Martyn Iles, managing director of the ACL. “Australia must not become the kind of society where some lives are considered worthier of life than others.”

Before the vote on Wednesday night, it was clear, when pairs for absent senators were not considered, that the bill had support from 18 Labor senators, nine Greens, four Coalition senators and six crossbench senators including Pauline Hanson, Leyonhjelm, Centre Alliance, Derryn Hinch and Tim Storer.

Over the course of Wednesday, the pool of undeclared votes shrunk with communications minister Mitch Fifield and Liberal senator Linda Reynolds breaking for the no side.

On Wednesday, Burston told Guardian Australia he now intended to vote no after “further advice and consultation”.

On Monday, a spokesman for Georgiou said he “supports the right for territories to choose their laws regarding euthanasia” which was “different to supporting the act of euthanasia”.

But in a speech to the Senate on Tuesday evening, Georgiou said he had decided “with a heavy heart” to oppose the legislation.

“Since meeting a group of doctors this week who are firmly against euthanasia, more questions have been raised, forcing me to question my stance on the issue. What are the safeguards that come with this legislation?”

He suggested that Victoria’s model of euthanasia did not contain adequate safeguards, and he was concerned that territories would gain the power to legalise euthanasia without “safety measures in place to capture only those that they are intended to serve”.

Georgiou suggested that “people who are just lonely or depressed” or who “have no family or feel they are a burden on society” would opt for assisted suicide.

He said palliative care had “fallen off the radar” and state and federal governments should focus on that before assisted suicide.

Labor’s Pat Dodson, Don Farrell, Helen Polley and Deborah O’Neill indicated they would vote against the bill. Liberals James McGrath and Richard Colbeck also said they were no votes.

O’Neill suggested proponents of the bill had asked senators to “avert our eyes” from the substantive issue of euthanasia to focus only on the element of territory rights in the bill.

Leyonhjelm had threatened that if the Turnbull government reneges on a deal to allow a free vote in the Senate and lower house, he may vote against unrelated government bills in retaliation.

The bill being defeated in the Senate has spared Malcolm Turnbull the political difficulty of having to choose between satisfying Leyonhjelm’s demands and those of several conservative ministers who did not want the bill to be voted on and passed in the lower house.