SALEM -- The Oregon Senate approved monumental increases to the minimum wage Thursday night, a major breakthrough on what's become the defining issue of the legislative session.

It was a watershed moment for Democrats, who after months of talk muscled through a bill they said would help people in Portland meet surging costs of living without hurting rural towns still strapped after the last recession.

Senate Bill 1532 passed 16-12, with Sen. Betsy Johnson, D-Scappoose, voting no with Republicans. The bill now heads to the House, where it faces another partisan fight.

The vote followed a six-hour floor debate -- the longest in memory at the Capitol -- that saw Republicans use a series of procedural maneuvers to lambast Democrats for moving too quickly and risking a massive blow to rural economies.

"We turn around and hurt everybody -- everybody -- by doing this," said Sen. Alan Olsen, R-Canby. "As you say on the left, we want progress. This isn't progression. This is the government intruding into our businesses and saying 'you will pay.'"

The Senate's six-year plan would give Oregon the highest minimum wage rates in the nation: $14.75 inside Portland's Urban Growth Boundary, $13.50 in a middle tier that includes Eugene and Bend, and $12.50 in sparsely populated "frontier" areas. Oregon's current minimum wage is $9.25, the eighth-highest in the nation. The federal minimum is $7.25.

Democrats responded, insisting the Legislature had to head off ballot measures seeking $13.50 and $15 while still offering wage raises for the neediest workers.

"These people, frankly, are hurting," said Sen. Michael Dembrow, D-Portland. "They do not want to rely on public assistance or charity just to get by."

The Senate plan replaces a deal reached between Gov. Kate Brown and some business leaders for $14.50 in the Portland area and $13.25 everywhere else.

Brown had revised an earlier proposal for $15.52 and $13.50 after businesses set out to undermine it.

Business groups indicated they wouldn't back down on efforts to derail the bill.

"It will kill jobs, harm consumers, force school and government service cuts and hurt Oregon farms and small businesses," Jason Brandt, president and CEO of the Oregon Restaurant and Lodging Association and spokesman for Defend Oregon Jobs, said in a statement. "We urge the House to defeat this plan that puts election year politics ahead of Oregon's economy."

Speaking on the Senate proposal Thursday, Brown raised no red flags, saying she's "very pleased the legislation is moving forward."

"It's important we act now to support working families throughout the state," Brown told reporters.

That the Senate would lead the minimum wage fight seemed impossible a year ago.

A bill in the 2015 session to give workers paid sick leave -- an issue far less divisive than minimum wage -- barely squeaked by. And Senate President Peter Courtney, D-Salem, said last year that adding the minimum wage would have been too much.

But in the weeks leading up to the 2016 session, the ballot measure threat and pressure from the left was enough to get moderate senators on board.

The Senate's proposal seemed to get buy-in from left-leaning groups that previously drew a hard line on a $13.50 minimum.

"We're in a place where we want to see it passed," said Andrea Paluso, executive director of Family Forward Oregon.

In a statement, Tom Chamberlain, president of the American Federation of Labor and Congress of Industrial Organizations Oregon chapter said the proposal "falls short of what workers need to support their families" but "marks a recognition that no matter where you live, Oregon's current minimum wage is not enough to live on."

Badly outgunned Republicans dragged out the debate for hours. They introduced half a dozen motions to refer the bill back to committees, suggesting amendments that would let cities and farms opt out, or give tax credits to small businesses. All were destined to fail.

Olsen, the Canby Republican, read aloud a list of people who'd signed a petition opposing the minimum wage increase.

At one point, Senate Minority Leader Ted Ferrioli, R-John Day, even quibbled with Courtney about the proper procedure for pounding the gavel.

"People from Portland," said Sen. Fred Girod, R-Stayton, "need to realize the world doesn't revolve around Portland."

-- Ian K. Kullgren

503-294-4006; @IanKullgren