Vermont is on the verge of becoming the ninth state to allow marijuana possession for recreational use and the first to do so through the legislative process.

The state legislature's lower house voted 79-66 Wednesday to allow adults 21 and older to possess 1 ounce and grow two mature plants, passing a bill the state Senate approved 20-9 on Friday.

Penalty-free possession would take effect in July 2018 and the bill would establish a nine-member commission to study retail sales, something authorized in the other eight states with recreational legalization laws.

But Gov. Phil Scott, a Republican, has not said if he will sign the bill, and his spokeswoman Rebecca Kelley says it may take weeks for him to decide.

“I can tell you we don’t expect to receive the bill from the legislature for a few weeks, and he will need to review the bill before making any decisions,” Kelley says.

In an email Wednesday evening, Kelley said changes to the bill – hashed out shortly before passage – mean he will need to review the final language.

“On the issue of legalizing marijuana, the governor has said he is not philosophically opposed, but we must ensure certain public safety and health questions are answered,” Kelley says.

Thus, Scott – who will have five days to sign or veto the bill when it reaches his desk, or it automatically becomes law – has invited an aggressive lobbying campaign.

Rep. Thomas Burditt, a Republican who supported the legalization bill, says he’s heard that Scott is receiving “hundreds, if not thousands” of phone calls and that roughly 95 percent are pro-legalization.

“I think he will let it become law without signing it,” Burditt says. “But that’s just a total guess.”

Kelley says she hasn’t heard of any policy position assessment of the phone calls and that 95 percent probably isn’t accurate, but Marijuana Policy Project lobbyist Matt Simon says he heard the same estimate.

Simon says supporters have seen “viral” responses to social media messages urging people to contact the governor.

Still, Scott – a former race car driver – has expressed concern about the difficulty of deterring drugged driving and preventing teen use.

Former Gov. Peter Shumlin, left, supported failed 2016 legislation to tax and regulate pot sales. Gov. Phil Scott, right, hasn't announced his position on a non-commercial legalization bill. (Toby Talbot/AP)

Vermont Public Radio reports that Scott has said marijuana legalization likely is inevitable but noted three considerations Wednesday.

“I believe that what we should be doing is trying to find ways to protect those on our highways, to deliver a level of impairment that is consistent throughout the Northeast, as well as to address the edibles for our kids before we move forward with legalization,” Scott reportedly said.

Burditt argues the 2018 effective date allows plenty of time to craft educational campaigns and train police to better detect drugged drivers. But technologies to accurately gauge driver impairment are only beginning to gain traction.

Roadside oral fluid tests that seek to judge how recently pot was used are gaining acceptance from courts, and breathalyzers are currently being field tested. Blood tests historically used on drugged driving suspects do not effectively gauge marijuana intoxication.

Despite Vermont’s national reputation as a bastion of progressive politics, there’s plenty of opposition to marijuana legalization in the state.

The non-commercial legalization bill passed only narrowly in the state House after the chamber soundly defeated a Senate-passed tax-and-regulate bill last year that was supported by then-Gov. Peter Shumlin, D-Vt.

“The Guv darn well better veto that sucker!” former Gov. Jim Douglas, a Republican, tells U.S. News in an email.

One consideration during this year’s debate is the fact that next-door Massachusetts and nearby Maine are moving to regulate recreational sales, as approved by residents in November. Canada’s Parliament also is moving to allow recreational sales with the support of Prime Minister Justin Trudeau.

"I'm speaking to you from a 15-minute drive to Massachusetts," Shumlin says. "Certainly all of southern Vermont is just going to Massachusetts to purchase marijuana and they know if they buy an ounce or less there's no real risk of enforcement in Vermont."

Vermont already allows medical marijuana and in 2013 abandoned criminal penalties for adult possession of up to 1 ounce of marijuana, which now is punished with a ticket of up to $200 for first offenses.

Former Gov. Jim Douglas, R-Vt., 2003-2011, says Gov. Scott should reject marijuana legalization. (Pablo Martinez Monsivais/AP)

"We're almost there, this bill just takes us a step further," Shumlin says. "This is a very modest, slow start."

The ex-governor says Vermont attracts about 4 million skiers a year and that legalization is "an economic development issue" with tens of millions of people within a short drive of the state. And he argues the commission to study retail sales will allow for thoughtful incorporation of lessons from other states. He would like a ban on edible sales, low enough taxes to eliminate the black market and reinvestment of proceeds into opioid addiction treatment.

But Kevin Sabet, a former presidential policy adviser who leads the anti-legalization group Smart Approaches to Marijuana, says the regional trend is “even more a reason not to do it.”

Vermont “would be able to attract businesses and families and communities that don’t want the influence of Big Marijuana,” Sabet says.

“What it is is the stepping stone to full retail legalization,” he says. “This is clearly a way for the marijuana industry to get a foothold in Vermont.”

Sabet says Scott should consider uncertainty about whether the Justice Department will crack down on states regulating recreational pot sales. The federal government cannot force states to re-criminalize personal possession but likely has the power to wreak havoc on the burgeoning multibillion-dollar state-legal cannabis industry.

If enacted, Vermont’s legalization scheme would initially resemble the framework in the District of Columbia, where adults 21 and older are allowed to possess 2 ounces and grow plants at home but where sales have been blocked by Republicans in Congress, which has authority over local budgets.

The breakthrough legislative victory in Vermont comes after years of voters pulling the trigger on legalization and dragging along reluctant politicians – first in Colorado and Washington in 2012, then Alaska, Oregon and D.C. in 2014, before voters in California, Maine, Massachusetts and Nevada last year.

The New Hampshire legislature's lower chamber was the first state legislative body to endorse a recreational legalization bill, in 2014 , but voted against it in a subsequent tally in the face of opposition from then-Gov. Maggie Hassan, a Democrat, and state senators. A Texas legislative committee voted 5-2 in 2015 to legalize marijuana and allow a free-market, loosely regulated retail system – though the bill went nowhere.

Vermont’s unique approval of pot legalization, however, may not last long. The reform is supported by roughly 60 percent of Americans, according to recent polls, and action is churning elsewhere.

The Delaware House Revenue and Finance Committee, for example, voted 7-2 Wednesday to approve a bill to regulate marijuana sales like alcohol. The bill is expected to have a floor vote in June but would require two-thirds support because it changes criminal law.