A bill to require criminal background checks on private gun sales passed the Oregon House on a 32-28 vote Monday and now goes to Gov. Kate Brown for her signature.

The hotly contested measure, Senate Bill 941, passed after nearly five hours of debate with 32 of the 35 Democrats in favor and all Republicans and three Democrats -- Jeff Barker of Aloha, Caddy McKeown of Coos Bay and Brad Witt of Clatskanie -- voting against.

Supporters of tighter gun laws have pushed hard for expanded background checks in the wake of the 2012 mass shootings in Newtown, Connecticut, and at Clackamas Town Center. Similar measures died in the Senate in 2012 and 2013, but the political dynamic changed after Democrats last year picked up two seats in the Senate and one in the House.

Brown has not spoken publicly about the bill yet but Sen. Floyd Prozanski, D-Eugene and the main architect of the measure, said he was confident the governor would sign it. He said he talked to her Monday morning and "she said she was thankful the bill will be coming to her."

Update: Gov. Kate Brown says she'll sign the gun bill

Supporters portrayed the measure as a common-sense step to close a loophole that allows many gun buyers to evade background checks. Opponents, meanwhile, said it would do little to stop gun violence while posing a particular burden on gun enthusiasts.

Everytown for Gun Safety, which has been financially backed by billionaire Michael Bloomberg, helped elect the two additional Democratic senators and waged an extensive lobbying and advertising campaign during this legislation session.

While the issue had been extensively debated in the Senate over recent years, it has not in the House. And supporters had trouble rounding up the 31 votes they needed since some Democrats from rural and suburban areas expressed doubts.

Rep. Brian Clem, D-Salem, said he supported the bill after he was promised follow-up legislation to provide more leeway for friends to lend guns to each other by being able to call the state police directly for a background check. SB 941 requires private sellers to go through licensed firearms dealers.

Oregon currently requires background checks on sales by licensed dealers and at gun shows to see if someone is a felon or otherwise legally prohibited from possessing a firearm. Under SB 941, Oregon would be the 12th state to require these checks on sales and transfers among private parties for both handguns and long guns.

"I do not want to take anyone's guns," said Rep. Dan Rayfield, D-Corvallis. "I do not want to register anyone's guns. I want to make the community safer."

He said Oregon's existing background check law stopped 345 felons and 37 people with mental health commitments in their past from buying guns in 2014, according to FBI statistics.

The measure has attracted particularly large opposition in small-town Oregon, where county commissions and local sheriffs have lined up against it.

"It shames me we did not talk to people in rural Oregon," said Rep. Jim Weidner, R-Yamhill, adding: "Sometimes you don't even know where the gun comes from in your truck."

House Minority Leader Mike McLane, R-Powell Butte, said the bill provides only the illusion of doing something useful.

"The tragedies at Sandy Hook, at Clackamas Town Center would not have been stopped by this bill," said McLane. He and other Republicans raised a flurry of situations in which the new background checks would interfere with longtime activities by gun owners.

Rep. Gail Whitsett, R-Klamath Falls, said she and her husband store most of their guns with a neighbor when they move to Salem before the session because it wouldn't be safe to leave the firearms in an empty home.

Rep. Jennifer Williamson, D-Portland and one of the bill's chief sponsors, said backers included several exemptions to try to ease the burden on legitimate gun owners. She noted that people can lend or transfer guns to relatives without background checks, as can military personnel going on deployment.

"We know that background checks work," said Williamson, citing statistics gathered by Everytown showing lower rates of some gun crimes in states with universal background checks.

Rep. Ann Lininger, D-Lake Oswego, cited the 2012 shooting death of Zina Daniel, a 42-year-old Wisconsin woman, by her estranged husband, who was prohibited from possessing a gun. He avoided a background check by buying a gun through a private sale.

"That's the kind of horror we're trying to protect against," Lininger said.

Democrats voted down a series of efforts by Republicans to send the bill back to committee or to replace it with measures aimed at boosting funding for mental health treatment and prosecuting people who have failed background checks.

Supporters said SB 941 also includes a provision requiring judges to rule whether someone receiving outpatient mental health treatment should be barred from gun ownership for a period of time. It also includes a provision requiring that local law enforcement officials be notified when someone fails a background check.

--Jeff Mapes

503-221-8209

@Jeffmapes