AUGUSTA –– A bill that gives Maine prosecutors the ability to pursue a 10-year prison sentence for out-of-state heroin traffickers advanced Wednesday despite arguments that proving drug importation in court is difficult.

The Maine Drug Enforcement Agency and other supporters of the bill said the threat of longer prison sentences will act as a deterrent to drug traffickers operating here.

“We have to show (traffickers) that if you come to Maine, you’re not going home,” said Sen. Scott Cyrway, R-Benton.

Opponents said Maine prosecutors already have the option of seeking stiff penalties for trafficking convictions. Others argued that there’s no evidence that stiffer penalties will lessen demand for the cheap heroin currently flowing into the state, and that lawmakers’ hastened response to the drug crisis is creating significant — and potentially harmful — changes to Maine’s criminal code.

The Criminal Justice and Public Safety Committee’s mostly party line vote was 6-4, with all Republicans in the majority.

The bill would increase punishment for importing almost all classes of illegal drugs. However, it was pitched as a response to a heroin crisis that Attorney General Janet Mills said Wednesday is likely responsible for 250 overdose deaths last year. Mills’ office did not take a position on the proposal, but she recently testified in support of another bill that would allow prosecutors to use the threat of a felony conviction for possession of heroin and other narcotics as a way to prod drug users into treatment.

The latter proposal was tabled by the Criminal Justice and Public Safety Committee after lawmakers wrestled with the consequences of hitting addicts with felony convictions that could follow them throughout their lives, potentially leading to the loss of their voting rights and making it difficult to obtain a job.

The panel was less hesitant to advance the importation bill, which would increase the maximum penalty for importing heroin into Maine from five years to 10 years. The maximum sentence for importing illegal drugs considered less serious would increase from 364 days to five years. Importing larger quantities of heroin, cocaine or other “Schedule W” drugs could trigger a new crime, “aggravated illegal importation,” carrying a penalty of up to 30 years in prison.

Overdose deaths from heroin and other opiates have surged in Maine and across the country in recent years, driven by a combination of tighter restrictions on prescription opiates, falling heroin prices and new, dangerously potent strains of the drug being sold. Maine had 174 accidental overdose deaths in the first nine months of 2015, with 71 caused at least in part by heroin. Mills told lawmakers Wednesday that additional analysis is likely to show that there 250 overdose deaths last year.

Those statistics and rolling media accounts of the crisis has prompted a slew of legislative proposals at the State House. In January the Legislature quickly passed a $3.7 million bill to hire additional drug agents and to expand treatment programs in the state. The bipartisan proposal, signed by Gov. Paul LePage, received a tepid reception from treatment advocates, although many were hopeful that it would hasten the flow of more treatment dollars. Meanwhile, proposals dealing with tougher penalties for drug offenses have exposed deep philosophical divisions about their efficacy.

Oamshri Amarasingham, an attorney with the American Civil Liberties Union of Maine, warned lawmakers in December about the “conflation between a moral mandate to take harm seriously and the solution of imposing a criminal penalty.”

“A sound policy does not reflexively assume that imposing more criminal penalties signifies a more serious engagement with the problem,” she said.

Others suggested that the importation proposal, L.D. 1541, isn’t the best law enforcement or deterrent tool.

“Our prosecutors in Maine . . . they use the most effective tools they have and they take this very seriously and they don’t use this (importation) statute,” said John Pelletier, a member of the Maine Criminal Law Advisory Commission, in December. “It is just not the most effective tool against this scourge.”

The reason, Pelletier reiterated Wednesday, is that proving importation is difficult. It’s not enough that police stop a vehicle with out-of-state plates loaded with heroin, he said. They also have to prove in court that the drugs were brought into the state from elsewhere.

Roy McKinney, the director of the MDEA, said that agents do monitor interstate trafficking. Although few individuals are charged with importation upon arrest, prosecutors often add the charge at the grand jury. McKinney acknowledged that proving importation requires additional procedures, including a court order, to track an individual’s movement across state lines. But, he said, stiffening the penalty will give his agents and prosecutors another weapon in disrupting the drug trade.

The bill will now go to the full Legislature for floor votes and potential amendments.