TRENTON — A monthslong effort to legalize marijuana in New Jersey collapsed on Monday after Democrats were unable to muster enough support for the measure, derailing a central campaign pledge by Gov. Philip D. Murphy and leaving the future of the legalization movement in doubt.
The failure in the Legislature marks one of the biggest setbacks for Mr. Murphy, who despite having full Democratic control in the State Senate and Assembly, has faced constant party infighting and has struggled to convince lawmakers of his progressive agenda.
Among the most vocal opponents were a handful of African-American Democratic lawmakers who split with their party over legalization, arguing that it would be a public health menace to their communities.
The abrupt unraveling of the campaign to legalize marijuana also reflected how some lawmakers were swayed by the challenges faced by other states that have legalized cannabis, including how to keep the drug away from teenagers and prevent people from driving under its influence.
The decision to scuttle the vote came after a frantic weekend push by Mr. Murphy to gain the votes he needed in the 40-member Senate.
“Certainly, I’m disappointed, but we are not defeated,” Mr. Murphy told reporters. “Justice may be delayed, but justice will not be denied.”
But it was unclear on Monday when leaders would revive the legalization effort.
The Senate president, Stephen M. Sweeney, said he “might have underestimated the challenge in getting this passed,” though, he too, vowed that he would not abandon the campaign.
Supporters of legalization said they were disappointed by the Legislature’s decision, but added that they would continue to press their case.
“Legalization is an urgent civil rights issue of our era, and it’s up to advocates in the coming weeks and month to make that urgency clear,” said Amol Sinha, the executive director of the New Jersey chapter of the American Civil Liberties Union.
The sweeping bill sought to redress what its supporters have said are the consequences of the war on drugs on minorities, and to tackle concerns about fairness in the multibillion-dollar cannabis industry.
The bill would have wiped away criminal records for hundreds of thousands of people convicted of minor drug offenses and legalized recreational marijuana in a state that borders the nation’s biggest city. It would also have given many in prison a chance to be set free and ended parole for many others.
The law also aimed to diversify a booming industry that has been dominated by white entrepreneurs in Washington, D.C., and the 11 states where recreational marijuana has been decriminalized. New Jersey would have ensured that members of minority groups, as well as women, have equal access to licenses to sell or cultivate cannabis.
“We have the widest white-nonwhite gap of persons incarcerated in America and far and away the biggest contributor is low-end drug offenses,” Mr. Murphy said recently at a news conference.
Though polls showed that most New Jersey residents support legalizing marijuana, Mr. Murphy had faced an uphill struggle since he made it one of his top priorities after taking office last year.
Some African-American lawmakers, in particular, could not be persuaded to embrace legalization, believing it would bring more harm than good to their communities.
“The public has not properly been educated on the topic of recreational marijuana,’’ said Senator Ronald L. Rice, a Democrat who represents Newark and emerged as one of the main opponents of legalization. “People don’t realize, particularly people in urban communities, how it will affect their lives. In urban communities, neighborhoods will struggle against the spread of ‘marijuana bodegas’ disguised as dispensaries.”
Still, changes to the bill’s final version, especially beefed-up measures to make it easier to expunge criminal records, attracted widespread support from civil liberties activists and criminal justice advocates in New Jersey and beyond.
“My concern had been that legal recreational marijuana has not dealt with the damage that has been disproportionately suffered by blacks and other people of color, and is just setting up people to make a lot of money,” the Rev. Al Sharpton said in an interview before the vote was canceled, adding that the bill was a “national model.’’
The effort to legalize marijuana has also been sputtering in New York, where black lawmakers have said they will block the implementation of the potential $3 billion statewide industry if the current bill does not ensure that minority entrepreneurs share in the profits.
New Jersey had been taking a more expansive approach than many other states to erase the criminal records of people charged with marijuana-related crimes. Anyone in New Jersey convicted of possessing up to five pounds would have been eligible to have their convictions erased.
The state was also seeking to make the expungement process easier by allowing it to be done online, eliminating the requirement to do it in person, which can be time-consuming and expensive.
Ever since Mr. Murphy had announced his support for legalizing marijuana as a candidate two years ago, expungement had been central to the debate. Supporters of legalization say stringent drug laws unfairly target minorities: A black resident of the state is three times more likely to be arrested on marijuana-related offenses than a white resident, a recent study found.
New Jersey was also moving to rewrite the vast racial and class disparity in the marijuana industry. White ownership makes up more than 80 percent of cannabis businesses across the country, according to a 2017 study.
In identifying communities that would have been granted licenses to cultivate, sell, distribute or produce marijuana products, lawmakers focused on places like Newark and Paterson, which have high rates of crime and unemployment. The legislation also would have allowed anyone with a past marijuana conviction to apply for a license to own a cannabis company.
The bill would have required that a minimum of 10 percent of licenses be given to smaller business, which are defined as those with 10 or fewer employees.
Some leaders in struggling New Jersey cities have said they believe the cannabis industry would benefit their communities.
“Social justice and economic development go hand in hand,” Mayor Reed Gusciora of Trenton said last week. “I walk in the streets and talk to many constituents that talk about a prior record and how it’s a hindrance for them to get ahead, get a job.”
Still, plenty of opposition to legal marijuana exists and dozens of communities had already voted to ban retail and growing operations in their towns. Some communities had also complained that the 3 percent local tax that could be added to retail sales was too low.
New Jersey had pieced together much of its plan from efforts elsewhere, though the state’s program would have featured a few differences.
Customers in New Jersey would have been able to have marijuana delivered to their door and would have been allowed to use cannabis in lounge-like settings similar to cannabis cafes found in California, Colorado and several countries in Europe.
The campaign also placed New Jersey at the center of a national conversation among Democratic presidential candidates over legalizing marijuana.
“All too often, communities of color and low-income individuals are unjustly impacted by our broken drug policies, but by including measures to expunge records and reinvest in the communities most impacted, our state has the opportunity to lead in prioritizing social justice,” Cory Booker, a Democratic United States senator from New Jersey who is running for president, said last week. He has introduced a federal bill that would remove the drug from the list of controlled substances.