Supporters of a measure to legalize the recreational use of marijuana in Oregon submitted 145,000 signatures Thursday to get the measure on the November ballot.

New Approach Oregon on Thursday morning toted cardboard boxes filled with petitions to the steps of the Multnomah County Courthouse for a news conference, then left for Salem to submit them to the Secretary of State's Office for approval.

Update, 3 p.m.: New Approach Oregon announced the petitions were delivered to the Secretary of State's office in Salem.

The office must vet the signatures by Aug. 2, although New Approach Oregon leaders said they hope to have a decision within the next three weeks.

At the news conference, six months after Colorado's law allowing recreational marijuana took effect, leaders stressed the ways in which their proposal is stricter than one Oregon voters defeated two years ago.

There were no marijuana leaf symbols, dreadlocks or even the color green to be found. Instead, leaders of New Approach Oregon and the American Civil Liberties Union of Oregon sported suit jackets and sought to project an air of safety and austerity.

"This is Oregon's opportunity to create a sensible approach to marijuana, and I hope many Oregonians recognize and support this," chief petitioner Anthony Johnson said. "We are going to fight for every single vote across this state."

The proposal, which seeks to legalize possession of 8 ounces of marijuana at home and 1 in public, would put the Oregon Liquor Control Commission in charge of regulating sales and distribution. Any tax revenue would be divided among police, schools, and programs dealing with drug prevention and mental health.

New Approach Oregon's proposal is backed by several major out-of-state donors, including the New York-based Drug Policy Alliance, which drafted Washington's successful proposal in 2012.

An Oregon Public Broadcasting poll published last month found 54 percent of Oregonians surveyed supported marijuana legalization. That figure is consistent with New Approach Oregon's internal polling data, spokesman Peter Zuckerman said, which also shows surprisingly strong support from rural conservatives and Libertarians who typically oppose such measures.

"The support is not ideological, it's a really broad spectrum," he said.

-- Ian K. Kullgren