Opponents of a ballot question to decriminalize the possession of up to an ounce of marijuana showcased their political muscle last Wednesday on a day in which the two sides traded barbs over the effects of marijuana use and even campaign finance practices.

At a press conference outside the capitol, district attorneys, mayors, religious leaders, concerned parents and Patrick administration officials, one by one, blasted the question. Passing such a proposal would set off a flood of violent crime, medical problems, impaired driving and youth drug use, they argued.

"Why would we want to put another monkey on society's back?" asked Suffolk County District Attorney Daniel Conley. "There is no public health or public safety benefit."

Opponents of Question 2 incorporated everything from alcohol abuse to OxyContin to gangster rap in their argument against the proposal, a stark contrast from the proponents who described the measure as a benign effort to refocus police on violent crime and to save costs on unnecessary arrests.

The opposition includes Gov. Deval Patrick, Mayor Thomas Menino, Somerville Mayor Joseph Curtatone, the TenPoint Coalition, the Black Ministerial Alliance, the Massachusetts Sheriffs Association, Mothers Against Drunk Driving and the Dorchester Youth Collaborative.

Backers of the question said despite the "sky is falling" approach of their adversaries, 11 other states that have passed decriminalization laws have yet to see spikes in pot use or related crime. They noted that laws governing the sale, trafficking and purchasing of marijuana would be left unchanged, as would any laws related to impaired driving.

But Cape and Islands District Attorney Michael O'Keefe cited a June Columbia University study that found marijuana potency had increased in recent years and had been tied to certain mental disorders and addiction.

The two sides bared their teeth throughout the day, each accusing the other of distorting the truth and of dubious or - in the case of the opponents - illegal fundraising activity.

Opponents of the question pointed out that much of the financing for the decriminalization of marijuana came from wealthy out-of-state liberal George Soros.

Proponents, on the other hand, filed legal complaints with the Office of Campaign Political Finance and the attorney general, arguing that the opposition had engaged in illegal, "covert" fundraising prior to forming a political committee, which they said is illegal under campaign finance law.

"These violations are clear-cut, non-disputable and documented," Committee for a Sensible Marijuana Policy campaign manager Whitney Taylor said at a sparsely attended morning press conference outside the Edward W. Brooke Courthouse in Boston. "For election officials to flout the very laws that have been placed in their capacity to enforce ... is unconscionable."

Taylor said her group filed complaints with the attorney general's office and the Office of Campaign and Political Finance alleging that the Coalition for Safe Streets, District Attorney John Blodgett, District Attorney Timothy Cruz and O'Neill and Associates illegally raised, spent or received funds before they had organized a political committee.

In a statement, the Coalition for Safe Streets said Question 2 backers were "clearly more concerned with the freedom to use drugs than the freedom of speech."

"The District Attorneys and the MDAA have worked closely with the Massachusetts Office of Campaign and Political Finance, received and followed guidance from them, and will continue to do so throughout this campaign," according to the statement. "The out-of-state pro-drug interests behind Question 2 are using desperate measures to try and distract voters from a genuine conversation about the devastating impact of more drugs in our communities. "

OCPF spokesman Jason Tait said the agency could neither confirm nor deny whether a complaint had been filed, a standard practice. He added, however, that under state law, fundraising without forming a ballot question committee could result in a $1,000 fine or a year imprisonment under state law. The more likely result, he added, would be to publicly disclose any violations, hammer out a monetary settlement, or to drop the case entirely.

Tait noted that the campaign against the ballot question had previously formed a political action committee that they used to raise initial funds and that "it was later brought to their attention" that they needed to form a ballot question committee, which they did on Sept. 5.