JUNEAU, Alaska -- The Senate voted Wednesday night by the barest of margins to approve a massive tax cut for the oil industry in the hope that it would lead to more oil production in Alaska.

The vote on Senate Bill 21 was 11-9, with only Republicans supporting the measure. Two other Republicans, Gary Stevens of Kodiak and Bert Stedman of Sitka, joined the Senate's seven Democrats in voting against the bill. With rural areas so dependent on state spending, two Democrats with large rural constituencies who are otherwise part of the Republican majority caucus, Donny Olson of Golovin and Dennis Egan of Juneau, voted against the bill.

The vote showed that the 2012 election, where redistricting helped knock off three Democratic senators, played a decisive role in changing the outcome on oil taxes. An oil tax bill pushed by Gov. Sean Parnell failed to make it through the Senate last year.

The vote was taken at 8:59 p.m. after hours of impassioned debate rarely heard in the Alaska Legislature. But the outcome had been all but sealed once an 11-9 vote along identical lines approved an amendment earlier in the day to slightly increase the tax on industry. That brought in the main holdout, Sen. Click Bishop, R-Fairbanks.

A video recording by KTUU Channel 2 of the votes going up on the tally board shows Bishop casting the 11th vote in favor of the bill.

The bill will cost the state treasury billions of dollars over the next decade, but supporters say it will eventually lead to greater oil production. Opponents say it's nothing more than a giveaway to the industry, which told the Legislature it would reduce its efforts here if it didn't get tax breaks even as it told stock analysts the opposite.

The bill throws out the five-year-old tax system known as ACES, for Alaska's Clear and Equitable Share. It became law through a coalition of Democrats, Republicans and Gov. Sarah Palin -- in her populist phase -- as way to undo the previous pro-industry tax regime that passed in 2006 under a cloud of corruption.

The measure will come up for reconsideration Thursday. Opponents said after the vote that they will continue to talk to Bishop in hopes of getting him to change his mind and force a do-over with a different result. In a 10-10 tie, the bill fails.

Talk of tax rates, net profits and exclusions dissolved into an epic debate on the future of Alaska and the meaning of the "owner state" Wednesday as the Senate warmed up for the vote.

"This is a bad bill that should be voted down," said Sen. Hollis French, D-Anchorage. "It's a giveaway, it's a crapshoot, it's a far, far cry from our best work and what we're capable of doing. I've watched each committee negotiate against themselves, waiting for some positive word form the oil industry. The words never came. In fact it was just the opposite. The last hearing, when the bill was in Senate Finance, I listened to senator after senator try to get the industry to commit to making more investments in Alaska if this bill passed. They declined to commit -- ConocoPhillips, British Petroleum, Exxon Mobil."

Sen. Cathy Giessel followed, saying she wasn't a lawyer like French, "but I have something of tremendous value, and that is, the life experience of living in the Territory of Alaska as well as the State of Alaska, and I've watched this state move from a very small economy before oil to what we enjoy today." But Giessel asserted that the economy is declining along with oil production. "I'm interested in seeing that robust economy come back. Right now, what we're seeing is a continued decline while other producing sectors in our country are seeing an increase in production -- Texas, North Dakota, California. ... Right now, we're seeing folks move out of our state."