SACRAMENTO — In stepping down as leader of Assembly Republicans on Thursday, Fresno lawmaker Mike Villines asserted that the GOP is prepared to dig in against any pressures for new taxes during upcoming budget negotiations.

Villines was replaced in a vote of the 29-member caucus by Assemblyman Sam Blakeslee, R-San Luis Obispo, who is considered a fierce opponent of tax increases.

The abrupt leadership change, observers said, signals that the Republican party remains steadfast on a core issue even as it struggles with a battered brand, including declines in voter registration and mounting political losses in the state and around the country.

"I think this summer you'll see people digging in and saying 'there's no way, you kidding?' " Villines said in a morning news conference. "You're not going to see taxes. We've done that. It's past us now, and we're moving forward and you won't see taxes."

Villines is the second leadership casualty among ousted Republicans in the last two months: Senate Minority Leader Dave Cogdill, R-Fresno, was replaced by conservative Sen. Dennis Hollingsworth, R-Temecula, on the eve of the budget vote.

Conservative groups hounded Villines for going along with $12 billion in new taxes as part of the budget deal legislative leaders hammered out in February.

"They appear to be out of step with the way elections are going, the fact that there's little dissatisfaction with President Obama, the welcome of big government in a time of need," said Larry Gerston, political science professor at San Jose State University. "But they don't believe they're out of touch with their constituents."

Democrats say Villines' ouster is another step toward irrelevancy for the Republican Party.

"When somebody gets beheaded for trying to fix the problems, it sends a message to voters," said Steve Maviglio, a Democratic consultant and former aide to ex-Assembly Speaker Fabian Nunez.

But Republicans call it a fresh start.

"There was a lot of frustration at the grass-roots level about the budget deal (reached under Villines and Cogdill)," said Tom Del Beccaro, the state GOP's vice chairman and former chairman of the Contra Costa County GOP. "This is step one toward getting us back to basic values of lower taxes. And we also need to put forth a strong reform agenda."

Being the party of 'no' won't work, said Bill Whalen, a research fellow at the Hoover Institution and former aide to ex-Gov. Pete Wilson.

"Do they want to be the party of steadfast denial or the party with an aggressive agenda?" Whalen said. "You know Republicans are against new taxes and higher spending. But you don't know what Republicans are for. That's what Republicans are missing. That's the test for Blakeslee and Republicans. What's their vision?"

Blakeslee, 53, first elected in 1994, is facing term limits at the end of 2010. After graduating with a doctorate in geophysics from U.C. Santa Barbara, he worked as a research scientist for Exxon before moving into management as a strategic planner. He and his wife Kara later formed an investment group.

"As Republican leader, I stand ready to lead our party to offer the realistic solutions Californians are demanding for the serious problems facing our state," Blakeslee said.

Villines was elected leader in late 2006 after the GOP caucus ousted George Plescia — for being too accommodating to Gov. Arnold Schwarzenegger. Considered one of the anti-tax stalwarts of the caucus, Villines said he was forced by circumstances to change, saying if he hadn't gone along with temporary taxes, Democrats would have found a way to impose permanent taxes. He will remain leader during a transition until June 1.

Reach Steven Harmon at 916-441-2101 or sharmon@bayareanewsgroup.com.