Senators have voted to pass the Trudeau government's landmark legislation to lift Canada's 95-year-old prohibition on recreational cannabis by a vote of 56 to 30 with one abstention.

Despite the resolute opposition of the 32 Conservative senators, and trepidation among some independent senators, Bill C-45 now moves back to the House of Commons.

MPs there will now have to decide what to do about the the almost four dozen amendments to Bill C-45 that were made in the Senate. The government will have to decide whether to approve, reject or modify the changes before returning the bill back to the Senate for another vote.

Health Minister Petitpas Taylor has said that, once the bill is passed, provinces and territories will need two to three months to prepare before retail sales of legal cannabis are actually available.

Most of the Senate's amendments are minor, but a handful are significant. One amendment would allow provinces to prohibit home cultivation of cannabis if they so choose, rather than accept the four marijuana plants per dwelling allowed under the bill.

Another amendment would impose even more stringent restrictions on advertising by cannabis companies, preventing them from promoting their brands on so-called 'swag', such as T-shirts and ball caps.

Yet another is aimed at recognizing that marijuana is often shared socially. It would make it a summary or ticketing offence for a young adult to share five grams or less of cannabis with a minor who is no more than two years younger, and it would allow parents to share it with their kids, as they can wine or other forms of alcohol.

A testy debate

Petitpas Taylor has refused to say how the government views the many amendments, but it appears to have given its blessing to at least 29 of them, which were proposed by the sponsor of the bill in the upper house, Sen. Tony Dean.

In their final speeches, Conservative senators betrayed frustration that most independent and Liberal independent senators appear poised to support the bill.

Before the vote Sen. Jean-Guy Dagenais predicted the vote would demonstrate "unprecedented acts of political blindness" as senators overlook the testimony of doctors, police and other experts about the serious health, social and public safety consequences of legalization in order to help Prime Minister Justin Trudeau deliver on an election promise. He accused them of "fickle partisanship."

"I don't believe for an instant that you have all together at the same time lost the independence that you claim to have," Dagenais said.

Like his Conservative colleague, Sen. Carolyn Stewart Olsen, Dagenais questioned the speed with which independent Indigenous senators abandoned plans Wednesday to propose an amendment that would have indefinitely delayed implementation of the bill until such time as the government files a report detailing how it is addressing the concerns of Indigenous communities that have complained about inadequate consultation.

Indigenous senators — who had been the Conservatives' best hope for getting the numbers needed to stymie the government's plan to have legal cannabis available by late summer — dropped the amendment after Petitpas Taylor and Indigenous Services Minister Jane Philpott sent a letter promising a full report to Parliament in September and another within 12 months. The ministers also promised more funding for Indigenous mental health and addiction treatment services, special help for Indigenous businesses to navigate the licensing process to grow marijuana and consultation on jurisdictional and revenue-sharing issues.

On Wednesday, Stewart Olsen told Indigenous senators they held "the hammer" that could have defeated or delayed the legislation but had, instead, chosen "seeming capitulation to the government" — remarks that were quickly denounced as patronizing by Sen. Murray Sinclair, former head of the Truth and Reconciliation Commission on residential schools.

Olsen's comments 'undeniably condescending'

Her intervention continued to reverberate Thursday and actually seemed to galvanize Indigenous senators to support the legislation.

Independent Liberal Sen. Lillian Dyck, to whom Stewart Olsen's remarks were addressed, said she "felt attacked personally." She called the comments "undeniably condescending," "unparliamentary" and "objectionable."

Dyck said Indigenous senators used their hammer "in a precise and focused action with great aim and achieved our objectives without undue collateral damage that a delay (in implementation) would precipitate."

Other Conservative senators predicted that Canadians will eventually rue the day cannabis is legalized.

"Legalization should be a last resort if incremental approaches to address cannabis-related harms fail," said Sen. Judith Seidman. "Instead, the government has chosen to conduct a grand experiment on the Canadian public, an experiment that cannot be undone."

Conservative Sen. Carolyn Stewart Olsen accused Indigenous senators of 'capitulation' on pot bill. (Fred Chartrand/Canadian Press)

She accused the government of creating "a multibillion-dollar, predatory cannabis industry overnight, with the provinces taking on the role of drug dealer and the federal government taking its cut."

But other senators argued that almost a century of criminalization has done nothing to stop Canadians, particularly young people, from using marijuana illegally and, thereby, creating a lucrative black market dominated by organized crime.

"There is one thing I know for certain," said Liberal Independent Sen. Art Eggleton. "Our current system is broken. It needs to be fixed."

Independent Sen. Andre Pratte said C-45 takes a pragmatic approach to regulating cannabis that is preferable to continuing the failed war on drugs.

"Do we take a deep breath, close our eyes and stick with a demonstrably failed, hypocritical, unhealthy, prohibitionist approach of the past or do we move forward, eyes wide open, and choose the alternative? ... I choose to open my eyes, rather than put on blinders," he said.