A TV ad showing San Francisco Mayor Gavin Newsom saying California is going to have same-sex marriage “whether you like it or not” is being credited with flipping poll numbers to favor the Nov. 4 ballot proposition to amend the state constitution to undo the state Supreme Court’s legalization of same-sex marriage.

“This door’s wide open now. It’s gonna happen. Whether you like it or not!” Newsom says in a clip included in the ad paid for by forces supporting passage of Proposition 8.

The ad continues: “Four judges ignored 4 million voters and imposed same-sex marriage on California. It’s no longer about tolerance. Acceptance of gay marriage is now mandatory. That changes a lot of things: People sued over personal beliefs. Churches could lose their tax exemption. Gay marriage taught in public schools. We don’t have to accept this. (‘Whether you like it or not!’) Yes on 8.”

Gay activists admit the ad is good, even though it contains “lies.” But equally important, they say, the pro-8 side has raised nearly $10 million more than the anti-8 side, allowing the forces that want to re-ban same-sex marriage greater access to the television airwaves.

The gay side’s current ad shows the parents of a lesbian pleading with voters not to “eliminate” marriage for anyone.

“Our worst nightmares are coming true,” Equality California Executive Director Geoff Kors said in an urgent fund-raising appeal Oct. 7. “Today we learned of the massive $25.4 million our opponents have raised so far. They are using this war chest to broadcast lies: 24/7 and up and down the state of California. And the polls show the lies are working. We need your donation now.”

Although other recent polls have shown opposition to Proposition 8 (which means one supports same-sex marriage) running as high as 55 percent, and support for Proposition 8 (which means one opposes same-sex marriage) running as low as 38 percent, two polls released Oct. 6 and 7 show voters now have flipped.

Equality California said its internal polling shows 47 percent of likely California voters want to re-ban same-sex marriage and 43 percent want to keep it legal. Likewise, a CBS 5/SurveyUSA poll found 47 percent support for a ban and 42 percent opposition to it.

“People change their minds about Proposition 8 when they hear the lie that churches will lose their tax-free status if they won’t marry same-sex couples,” said Kors. “Even though this is not true.

“So this is crunch time. With less than a month before the election, we must get on the air now to answer these lies and swing votes back to our side. And the only way to do that is to raise more money. The generous $15.8 million that our supporters have given isn’t enough.”

The new EQCA polling, a compilation of the group’s daily tracking polls, was conducted by Lake Research Partners. It questioned 1,051 randomly dialed likely voters between Sept. 29 and Oct. 2 and has a margin of error of plus or minus 3.1 percent.