A measure that would decriminalize minor marijuana-possession cases is on the ballot in Massachusetts largely because of one man: billionaire financier and liberal activist George Soros.

Of the $429,000 collected last year by the group advancing the measure, $400,000 came from Soros, who has championed similar efforts in several states and spent $24 million to fight President Bush's 2004 re-election bid. The Committee for Sensible Marijuana Policy needed about $315,000 of that just to collect the more than 100,000 signatures that secured a spot on the ballot, according to campaign finance reports reviewed by The Associated Press.

"All of us owe George Soros a great deal of gratitude," said Keith Stroup, founder of NORML, the National Organization for the Reform of Marijuana Laws.

If the measure is approved in November, Massachusetts would become the 13th state to lift or ease criminal penalties on marijuana possession. The proposal would make having an ounce or less of the drug a civil offense punishable by a $100 fine.

A spokesman for Soros referred questions to Ethan Nadelmann, executive director of the New York-based Drug Policy Alliance. Soros' efforts to ease penalties for drug crimes have come through the alliance, where he is a member of the board of directors.

Nadelmann said Soros feels the war on drugs is draining money and resources that could be better spent.

"He thinks the (ballot question) is a responsible initiative to reduce the overreliance on criminal justice sanctions in dealing with marijuana," Nadelmann said. "Marijuana should not be a priority of the criminal justice system."

Soros is credited with putting financial muscle behind many of the state initiatives easing marijuana laws — beginning with a 1996 California ballot question to allow marijuana use for medical purposes. From 1996 to 2000, Soros backed medical marijuana questions there and in Alaska, Oregon, Washington, Colorado, Nevada and Maine.

More recently he has focused on criminal justice reform efforts including pushing a proposal in California this year that would prohibit sending drug offenders back to prison for parole violations unless they commit a new felony, have a violent or serious record, or are considered high risk by prison officials. He has also contributed to Barack Obama, Hillary Rodham Clinton and Joe Biden and has helped support a group running ads opposing Republican John McCain.

Soros's wealth was estimated at $8.8 billion by Forbes magazine last year. He was also the second-highest-paid hedge fund manager last year at $2.9 billion.

Critics say marijuana decriminalization sends the wrong message to young people — that using drugs carries few consequences. Not only are there health risks associated with marijuana, they say, but users often end up moving on to more dangerous illegal drugs.

Middlesex District Attorney Gerard Leone said the marijuana being sold on the street these days is more potent than that sold three decades ago.

"Decriminalizing marijuana is a slippery slope and sends the wrong message," he said. "Compounding this is the fact that users of marijuana are 10 times more likely to be injured, or injure others, in automobile crashes."

Leone said marijuana possession is already treated less stringently in the courts than other drugs.

The question has been criticized by others in law enforcement and drug education groups like DARE-Massachusetts — but according to the secretary of state's office, opponents haven't created a group to raise money to fight the question.

A whopping 72 percent of Massachusetts' voters favored the ballot question and 22 percent opposed it according to a WHDH-TV/Suffolk University poll of 400 registered conducted from July 31-Aug. 3. The poll had a margin of error of plus or minus 5 percentage points.

Whitney Taylor of the Committee for Sensible Marijuana Policy said the question would help unclog the courts, save the state millions and spare thousands of residents the burden of a criminal record.

The question requires parental notification and the completion of a drug awareness program for anyone under 18 caught with an ounce or less of the drug. It bars the possession of an ounce or less of marijuana from being used to deny financial aid, public housing or other public assistance, drivers' licenses or the ability to be a foster or adoptive parent.

"They can move on and get a student loan and get their first apartment and move on with their lives," Taylor said. "People recognize that there are a lot better things we could be doing with our police resources."

Currently, possession of small amounts of marijuana in the state is punishable by up to 6 months in jail and a $500 fine. Taylor said offenders commonly get probation, but even in those cases the criminal convictions stay on their records.

The only other statewide vote this year on marijuana laws will be in Michigan, where voters are weighing an initiative to allow patients to grow and use small amounts of marijuana for relief from pain associated with cancer, AIDS, multiple sclerosis and other diseases.

If Massachusetts voters approve the ballot question, according to NORML, the state would join a dozen others which have to some extent decriminalized first-time possession of small amounts of marijuana for personal use: Alaska, California, Colorado, Maine, Minnesota, Mississippi, Nebraska, Nevada, New York, North Carolina, Ohio and Oregon.