Measure 97, the $3 billion corporate tax increase, lost big tonight.

Early returns show the measure trailing, 56 percent to 43 percent.

As recently as Sept. 8, polling showed that 60 percent of voters supported the measure but it withered under the largest onslaught of spending Oregon has ever seen.

Opponents of the tax hike, mostly large out-of-state corporations, have raised $26.5 million so far. That's $10 million more than supporters of the tax, mostly public employee unions, have raised.

In a small conference room, Hanna Vaandering, president of the Oregon Education Association and other supporters of Measure 97 struck a defiant tone.

"We've started not just a campaign but a movement," Vaandering said, as a group of supporters waved signs saying "It's Time for Corporate Accountability."

"We're taking this coalition to Salem and we're not backing down," Vaandering said.

Ben Unger, the executive director of Our Oregon, which put Measure 97 on the ballot said the tax hike lost support "under the slow, crushing weight of the money" opponents raised.

Former Oregon Gov. Ted Kulongoski, attending the the Democratic Party of Oregon victory event at the Oregon Convention Center, said Measure 97 proved too ambitious a grab for corporate cash.

"I think the voters believe that corporations should pay more," Kulongoski said, "but what they seem to have said is $6 billion is too much."

That was the case for semi-retired Southwest Portland voter Janie Logan, a Democrat attending the election-night party who said Measure 97 was a key issue to her. She voted against it.

"I didn't like the idea that the money wasn't tied to specific causes," Logan said, "to be used for specific things."

The "no" campaign, Defeat the Tax on Oregon Sales celebrated their victory without fanfare.

"Our coalition ran a fact-based campaign outlining Measure 97's flaws. We're grateful Oregonians agreed with us and rejected the costly and damaging proposal," said Rebecca Tweed, the manager of the "No" campaign in a statement. "Voters didn't buy claims that the $6 billion tax, based on business sales instead of profits, would not increase consumer costs. And they understood that the money raised could have been used any way legislators wanted to spend it. "

WW news intern Piper McDaniel contributed to this report.