TRENTON, N.J. (AP) – New Jersey legislative leaders unveiled a proposed ballot question Monday that would ask voters whether the state should legalize recreational marijuana.

If the proposal to amend the state constitution is approved in 2020, New Jersey would join the District of Columbia and 11 other states that have legalized recreational pot.

Democratic Senate President Steve Sweeney and Judiciary Committee chairman Nicholas Scutari unveiled the proposed ballot question in an email and said they plan to vote on it in the coming weeks.

The proposed question calls for legalizing the drug only for adults who are at least 21. It also calls for the state’s medical marijuana commission to oversee the new market and would subject sales to the state’s 6.625% sales tax.

“This initiative will bring cannabis out of the underground so that it can be controlled to ensure a safe product, strictly regulated to limit use to adults and have sales subjected to the sales tax,” the legislators said in a statement.

The ballot question is an about-face since lawmakers had earlier said they preferred to legalize the drug through legislation, rather than through the ballot box. They argued at the time legislation would provide them flexibility that changing the state constitution lacks.

But when backing for legalization legislation fizzled in the state Senate in March, it became increasingly clear more recently that legislative leaders would push a referendum instead.

Legalization of marijuana for those 21 and older has support among the state’s Democratic leaders, including Gov. Phil Murphy. Despite their support, the issue has failed to garner enough support among rank-and-file lawmakers.

In statement Monday, Murphy said he was disappointed the legislation failed to succeed but seemed to embrace the proposed amendment.

“I have faith that the people of New Jersey will put us on the right side of history when they vote next November,” the first-term governor said.

Democratic Speaker Craig Coughlin said through a spokesman the Assembly will also vote on the proposal.

Lawmakers will put the question on the ballot if they approve it by at least a three-fifths majority in one legislative session, or if the question is approved by less than three-fifths’ majorities in two back-to-back sessions.