The Liberal government's announcement that it will expedite the processing of pardons for people with minor cannabis-related criminal records is welcome news to tens of thousands of Canadians who have been convicted of possession offences.

And while the Parole Board of Canada might soon be inundated with record suspension requests — more than 500,000 Canadians have a criminal record for having pot on their person, according to a 2014 study — advocates claim the Liberal plan might not go far enough to reverse decades of "historical injustice" from cannabis prohibition.

The number of Canadians convicted of simple pot possession offences each year has been on the decline since Prime Minister Justin Trudeau announced his plan to legalize and regulate the drug. His 2015 election victory all but assured a legal change — and yet some 55,000 Canadians were arrested for cannabis-related offences in 2016 alone (of those 41,800 were for possession), according to Statistics Canada.

Even if one were to assume many of those arrests do not ultimately result in convictions, the number of Canadians with a criminal past for possession of the drug — one that is now legal — is still a staggering figure.

Watch as Trudeau speaks about cannabis legalization:

The Prime Minister spoke to reporters as he arrived for his weekly caucus meeting on Wednesday morning 2:25

Thus, the government's pledge to waive the steep fee for a record suspension (pardon) — it normally costs $631 — and do away with the standard waiting period (five years for a summary offence, 10 years for an indictable offence) could be a truly life-changing move for a sizeable minority of Canadians.

"I think today's a historic day. Canada is doing something monumental," Akwasi Owusu-Bempah, the director of research at Cannabis Amnesty, a not-for-profit that has fought for a solution for those with criminal records for cannabis possession, said in an interview on Wednesday.

"It's fantastic to hear the government is recognizing the harms that have been done by criminalizing people," he said.

Public Safety Minister Ralph Goodale said the pardons will "shed the burden and stigma" and break down barriers to jobs, education, housing or volunteer work.

A record suspension does not erase the fact someone committed a crime. Rather, it keeps the record separate from other criminal records in the Canadian Police Information Centre (CPIC) database.

Lack of a pardon timeline problematic

The government was light on details Wednesday — affirming only that the process would be free, and waiting periods would be eliminated — while promising legislation would soon be introduced in the House of Commons.

Michael Spratt, a prominent criminal defence lawyer in Ottawa, said the pardon pledge is a "step in the right direction" but the lack of a firm timeline is problematic.

"It's a bit charitable to call it a plan. There's no legislation before Parliament and there aren't many details," Spratt said in an interview with CBC News.

"A lot of things remain to be seen about how it's actually going to play out and, given the upcoming election, if it's going to play out at all."

A big question for Spratt is just how broad the government will "cast the pardon net," and he questions whether the application process will be open to people convicted of other offences or for people who have breached probation.

With a standard processing time of 6-12 months for a record suspension, people with a history of cannabis convictions are still at least a year away from having some form of record relief.

"A plan to deal with historic marijuana offences is something the government shouldn't have waited on. It's widely acknowledged the devastating harm that a criminal record can have and so every day we delay in correcting those injustices is a day too long," Spratt said.

A woman smokes marijuana during a 4/20 rally in Toronto. (Mike Cassese/Reuters)

When asked why a bill was not already drafted and ready for introduction Wednesday — the legalization date has been known for months — Goodale said the government did not want to pursue such a regime until the 100-year-old prohibition of the drug was officially lifted.

Pardons have limitations

And despite the promise of having a record suppressed, criminal lawyers are warning that a pot pardon has its limitations.

Firstly, it is not an expungement, which is another, far more robust form of record relief for people who have been convicted of a crime.

An expungement goes one step further than a pardon, destroying all known government records of the offence.

When an expungement is ordered, the person convicted of the offence is deemed never to have been convicted of that offence in the first place. With a pardon, a person is still considered a past criminal and they would still have to check the "convicted of a criminal offence" box on an application for housing or employment.

Watch as Prime Minister apologies to LGBTQ people:

The Prime Minister apologizes to LGBT people who lost their careers in the military and security services because of the sexual orientation 1:06

The government recently offered to expunge criminal records for LGBTQ people who were convicted of certain crimes that have now been deemed "historically unjust," with eligibility limited to three offences: gross indecency, buggery and anal intercourse.

Owusu-Bempah said a similar expungement should be extended to people with a cannabis possession criminal history in large part because those laws were often applied disproportionately to Indigenous people and black Canadians.

"I think historical injustices come in to play [with cannabis] as it was done with crimes of buggery. There were disparities across the country in the application of some of the law. Indigenous populations and black peoples have been saddled with the impact of a criminal record, the burden of a criminal record, when the drug has been widely used," Owusu-Bempah said.

A spokesperson for Goodale said while there is no doubt "certain communities have been disproportionately affected" by the way cannabis laws have been enforced, "expungement is an extraordinary measure intended to be used when the injustice is inherent in the law itself, as was the case with the prohibition of sexual activity between same-sex partners, rather than a matter of how the law is enforced."

Application process onerous for marginalized people

Spratt said many of the people who have been hit with possession-related charges in recent years — even as police have slowed such activity — are overwhelmingly marginalized groups like racial minorities, people with prior records or mental health issues, and the poor.

"I've definitely seen a decrease in white, middle class university students who are facing these charges," he said.

Spratt said many disadvantaged people will have trouble fulfilling the "onerous" process required to apply for a pardon, including obtaining court records, procuring digital fingerprints and generally fulfilling all the other requirements of the 10-step process.

Prime Minister Justin Trudeau wipes his eye while he is applauded as he delivers a formal apology to LGBT people in Canada in the House of Commons in Ottawa, Tuesday, Nov.28, 2017. (Adrian Wyld/The Canadian Press)

"I don't think it would be unreasonable to just offer blanket expungements for those offences," Spratt said. "I'm worried the process ... might still have some disproportionate impacts on some of the very people you want to help."

Spratt also noted the government said Wednesday a person has to complete their criminal sentence before applying for a pardon, which includes paying all fines and victim fine surcharges that might be associated with a conviction.

"A $500 fine might be something that a more affluent person can easily pay but if you're living in poverty, and your drug record is preventing you from moving ahead in a pro-social way, it might be difficult to pay off those fine orders before the pardon is available," he said.

Moreover, even if one is successful in securing a pardon, it does not mean it will make it easier to cross the Canada-U.S. border.

No guarantees at U.S. border

The U.S. Custom and Border Protection agency was clear Wednesday: the U.S. recognizes foreign convictions for something that would be a crime in their country, and it does not recognize foreign pardons.

Speaking in Buffalo, Richard Roberts, the CBP assistant director of border security, said Canadian pardons or "amnesty" are simply not considered under U.S. border admissibility law.

Watch as Public Safety Minister warns Canadians who use cannabis about issues at the U.S. border:

Public Safety Minister Ralph Goodale warns Canadians who use pot that crossing into the United States isn't a guarantee just because it's now legal in Canada. 1:36

"They could still be found inadmissible," he said. "Yes the law has changed [in Canada] but really, at the border, this is business as usual for us."

But Goodale's office noted, in the case of the U.S. border, there might actually be an upside to government offering pardons rather than expungements for cannabis offences.

"If the United States has a record of your expunged conviction and denies you entry, there will be no records to retrieve while seeking a waiver to enter the U.S.," a spokesperson said.