BOSTON U. — Nearly two weeks after voters overwhelmingly approved Question 2, a measure to decriminalize possession of less than one ounce of marijuana, police groups that have publicly opposed the measure have their own follow-up: Why bother?

Under the law, which will take effect Dec. 4, officers in Massachusetts will issue a fine to individuals in possession of an ounce or less of marijuana instead arresting them.

The question’s approval will put police in a non-enforcement conundrum by forcing them to treat marijuana violations as a lower priority, Boston Police Patrolmen’s Association Area A-1 representative James Carnell said.

“Smoking weed will become similar to jay-walking, where you have a law that’s totally not enforced because it’s a waste of everyone’s time,” he said.

Carnell said it is not worth an officer’s time to seize the drugs and fill out all the necessary paperwork for a citation under the new law and $100 fine when the fined individuals are not even required to show a valid form of identification.

“It would serve no purpose to hand out citations to people who are under no obligation to provide a positive photo ID,” he said.

Often those arrested for marijuana possession are breaking other laws and without making an arrest, it will be harder for officers to investigate these crimes, Carnell said.

“This is just one other tool out of our hands to do anything about crime,” he said.

There is no way to predict how Massachusetts’ police will handle the oncoming changes, Carnell said.

“There is a whole range of issues that still haven’t been addressed and it is the street level officers who will be confronted with these issues,” he said.

Last year, the Committee for Sensible Marijuana Policy proposed the new law because the group said arrest records unfairly hurt offenders’ chances to get jobs or secure financial aid, CSMP chairwoman Whitney Taylor said.

“Lifetime barriers created by involvement with the criminal justice system are too harsh,” she said. “We want the penalty to fit the offense.”

Taylor said a criminal record makes it difficult for people to obtain jobs, housing and student loans, and the new law will reduce these struggles for many people. The law is not meant to promote the use of marijuana, which is still an illegal substance, she said.

“Eleven other states have passed similar laws and what we’ve seen is that it does not affect marijuana usage rates at all,” Taylor said.

Though the measure will soon take effect, Taylor said the CSMP will continue to work with Massachusetts police to insure the proper enforcement of the new marijuana policy.

“We will be working with others to make sure law enforcement officials and officers on the street enforce the law correctly,” she said.

Anti-drug groups like Massachusetts’ Drug Abuse Resistance Education will continue to discourage drug use, D.A.R.E. Executive Director Domenic DiNatale said. Still, he acknowledged some laws, no matter how stringently enforced, are powerless to influence some people.

“People are going to use [marijuana] regardless of what the law says,” he said.