New Jersey approved a constitutional amendment legalizing marijuana for adult use on Tuesday by a ratio of about 2 to 1.

With the historic vote, New Jersey became the first state in the Mid-Atlantic region to adopt legal cannabis, creating a potential $2 billion market and making it likely that criminal arrests for marijuana will be curtailed. The decision represents a potential bonanza for state taxpayers and will put pressure on Pennsylvania and New York to follow suit, experts say.

“New Jersey voters have mandated an end to cannabis prohibition, and they have voiced their support for building an equitable, just market in place of unfair and outdated drug laws,” said Axel Owen, campaign manager for NJ CAN 2020, which led the public relations effort to legalize the substance.

So will legal weed go on sale to everyone over 21 anytime soon?

“Definitively, no,” said Jeff Brown, assistant commissioner for the Office of Medicinal Marijuana at the New Jersey Department of Health. “How soon will be determined by what the legislation looks like. That has yet to be written by the Legislature."

The amendment allows for a state tax rate of 6.25% on sales. Everything else would be in play.

The regulations to govern the new legal industry may take several months — or even years — to work out, depending on what political roadblocks spring up in Trenton.

New Jersey was one of four states this year with referendums to legalize cannabis on the ballot; the others were Arizona, Montana, and South Dakota, where the votes still hadn’t been counted last night. Until Election Day, 34 states, including Pennsylvania and New Jersey, had enacted laws to allow medical marijuana. And 11 of those states had made cannabis available to all adults.

Appearing in Willingboro on Tuesday, Gov. Phil Murphy underscored his enthusiasm for recreational marijuana.

“I got to supporting it first and foremost due to social justice,” Murphy said, following an appearance with U.S. Rep. Andy Kim (D., N.J.) “We inherited when I became governor the largest white, nonwhite gap of persons incarcerated in America and the biggest contributor to that was low-end drug offenses."

“We’ll work with the Legislature to that get up and running," Murphy said. "And we’ll address one of the biggest social injustices in our state, and at the same time, by the way, secondarily, but importantly, will create jobs and economic activity.”

The New Jersey constitutional amendment will take effect on Jan. 1.

The scope of the law will depend on what model the Legislature adopts.

Lawmakers could decide to “flip the switch” and allow current medical marijuana retailers to sell to a broader adult market. The Legislature could revisit a previously stalled legalization bill, and rush it through. Both options would keep all cannabis sales under a tightly regulated regime and in a small number of hands, similar to the program underway in Illinois.

Marijuana advocates have no enthusiasm for those plans.

“The existing Big Marijuana cartel has shown an inability to handle the very limited patient population” under medical marijuana, said Chris Goldstein, a regional spokesperson for NORML, the National Association for the Reform of Marijuana Laws. “They’ve been unable to maintain supply, they’ve proven they can’t get in gear to make home deliveries, and their prices are too high.”

New Jersey during the last two years has added only six medical licensees. Oklahoma, during the same period, added 2,200 medical dispensaries.

“I’d prefer a free and open market similar to Oklahoma’s,” said Scott Rudder, a lobbyist and president of the New Jersey Cannabis Association. “We could do it in the same way we have with pharmacies and liquor stores. You meet certain criteria, pay a fee, and you get the OK.”

With the vote, New Jersey becomes the most populous state on the East Coast to legalize recreational weed.

Currently in both New Jersey and Pennsylvania, the deck is stacked to favor big corporations or investors with deep pockets. Obtaining a permit, zoning, and a storefront for a new cannabis retailer can cost up to $1 million. Rudder would prefer to see a fee closer to $2,500.

“We want to make sure that we don’t skip over Main Street and go straight to Wall Street,” said Rudder, a former Republican assemblyman.

Whatever the state adopts, advocates said the Legislature will first have to swiftly adopt a bill to end criminal arrests for marijuana even before the broader sales regulations are worked out.

“We must ensure we stop arresting people for marijuana possession,” said Bill Caruso, who heads the cannabis practice at Archer Law. “Hopefully it happens this month, but it needs to happen before the end of the year.”

New Jersey will allow Pennsylvanians to buy weed in the Garden State, but federal and Pennsylvania state law will ban Keystoners from transporting it back home. Analysts nonetheless expect Pennsylvanians and New Yorkers to make substantial purchases in New Jersey.

Approaching the election, polls showed the legalization measure had overwhelming support.

The handful of opponents included Kevin Sabet, founder of Smart Approaches to Marijuana and a former White House adviser on drug policy to President Barack Obama.

Supporters of legalization raised about $2.1 million. That money came primarily from the ACLU of New Jersey, which advocated for the amendment as a way to improve social justice and end the documented racial disparities among pot-related arrests.

More than $800,000 was donated by a foundation funded by Scotts Miracle-Gro, which makes hydroponic equipment and fertilizers often used to grow marijuana.

The total spent was tiny compared with the average of $8.3 million spent to legalize cannabis in other states, said the Election Law Enforcement Commission.

Acreage Holdings, a multistate marijuana grower and retailer, was the only Big Marijuana firm to contribute to the cause, and with a relative paltry sum of $20,000. Acreage operates dispensaries under the name the Botanist.

“The money put in by corporations will pay dividends," Sabet said. "But the people of New Jersey will be shortchanged through increased mental health costs, student school problems, and impaired driving. I’m particularly worried about the last. Those jug handles are already tough to navigate. Now there’s going to many people trying to drive on them while they’re stoned.”

Staff writer Amy S. Rosenberg contributed to this article.