We've seen marijuana tax revenue used to build schools and sidewalks, fund college scholarships, and help people who are homeless. But the latest use proposed for Oregon's state tax on marijuana is among the most sensible we've heard yet: actually helping to expunge the records of people who have been charged with marijuana-related offences.

At a meeting yesterday, Portland City Council voted to refer a proposal to add a 3 per cent sales tax on marijuana to the November ballot, where voters will decide its fate.

Oregon's state tax on marijuana will drop to 17 percent next year: if voters approve, it's estimated to boost local tax revenue to about $3-million per year.

Portland City Commissioner Amanda Fritz proposed spending some of that $3-million on public safety and drug treatment initiatives, business incubators, and other social programs - but also on helping people unjustly prosecuted under marijuana prohibition.

"For instance," Fritz say, the tax revenue could be "helping with expunging people's records who were convicted of cannabis-related crimes that wouldn't be a crime now."

She also suggested the taxes could also be used to provide "economic opportunity and education to communities disproportionately impacted by cannabis prohibition."

Fritz said conversations with marijuana industry lobbyists helped influence her proposal.

Oregon is a national leader on record expungements

How states will assist those prosecuted under prohibition is a matter of serious debate, with some further ahead than others. As it prepared to introduce a legal market last fall, Oregon started allowing state residents to apply to have their possession records expunged, using an already existing state law.

This is a critically important step that makes it easier for people with prior convictions to apply for jobs, secure mortgages or do volunteer work for their communities. But there are fees associated with the expungements, which makes the proposed tax initiative crucial for people with limited financial resources.

Oregon is further ahead than most states, though, who haven't yet made state-wide accommodations to allow for expunging prior records. Last fall, the city of Spokane, Washington, grew impatient with failed state-wide efforts and passed its own law to vacate convictions for minor misdemeanour possession.

If voters approve the proposed measure in November, the Portland tax will come into effect January 1, 2017.

h/t The New York Times, The Portland Mercury, The Huffington Post.