Lawmakers who assumed an override of a governor's budget veto would be easy learned differently Wednesday.

As they sent Gov. Arnold Schwarzenegger a budget he opposed this week, legislative leaders of both parties said they were confident they could override a gubernatorial veto. That takes a two-thirds vote, the same threshold required to pass the budget bill in the first place.

But complications surfaced Wednesday because the linchpin of the spending plan – an attempt to raise nearly $4 billion by accelerating tax payments – was passed in separate legislation using a procedural maneuver that required only a majority vote.

That allowed Republicans to sidestep an action that political opponents could call a tax increase.

To override, Republicans will have to cast votes on that measure.

Assemblyman Alberto Torrico, a Newark Democrat who serves as majority floor leader, said the controversy adds to an "absolute mess" surrounding the state's record 80-day budget standoff.

"I think it's going to be a significant problem," he said of garnering enough GOP votes – at least six in the Assembly, two in the Senate – to override a veto of the tax bill.

The development gives Schwarzenegger substantially more leverage as he seeks to alter the deal lawmakers struck without him over the weekend.

If Republicans were to stand firm on their Tuesday votes, the lawmakers' budget wouldn't balance and they would be forced back to the drawing board. California's constitution requires a balanced budget.

Schwarzenegger spokesman Aaron McLear said the governor's goal is passage of a state budget that does not push fiscal problems into next year and cracks down on future spending.

"We'll work with them to do the right thing," he said of lawmakers.

Legislative leaders, who met with Schwarzenegger on Wednesday, were hesitant to speculate on how events will play out.

"We cross that bridge when we get there," said Steve Maviglio, spokesman for Assembly Speaker Karen Bass, D-Los Angeles.

"Everything is wait and see," said Alicia Trost, spokeswoman for Senate President Pro Tem Don Perata.

The tax-acceleration bill opposed by Republicans calls for raising billions this fiscal year by advancing collection of income taxes, then refunding overpayments later. The state essentially would receive a short-term, interest-free loan from taxpayers.

Schwarzenegger called the measure a smoke screen that cuts paychecks.

"It's really increasing the taxes, and they're putting a burden on taxpayers," he said at a Capitol press conference Tuesday.

Supporters of the measure disagree.

They argue taxpayers would not pay more in taxes but would just remit payments sooner – and they could avoid any impact by altering the withholding forms they file with employers.

GOP legislative leaders have publicly supported overriding a gubernatorial veto on the primary budget bill. Prospects for the tax-acceleration bill are less certain.

"It does create some heartburn for Republicans," Sen. George Runner, R-Lancaster, said of a second vote on the trailer bill. "Will it create enough that they wouldn't go up on an override? I don't know."

Senate Republican leader Dave Cogdill of Modesto, who voted against the tax-acceleration bill Tuesday, is willing to help line up GOP votes for it if necessary for an override, spokeswoman Eileen Ricker said.

Assembly Republican leader Mike Villines of Clovis could not be reached for comment.

Because the bill did not actually raise taxes, only accelerated collection, state law allowed it to be passed Tuesday by a simple majority of each legislative house as part of a special session on budget matters.

Assemblyman Anthony Adams, R-Hesperia, voted against the tax acceleration Tuesday but said he would be willing to reconsider, if pressed.

"It's not desirable, but at the same time, the governor is playing games with California families – and if we have to step in and provide the only real leadership in the Capitol, then so be it," Adams said.

Republican Assemblyman Chuck DeVore of Irvine characterized the tax-acceleration bill as "taking money out of people's pockets." He has not decided, however, whether he would support an override as a last resort to save the budget package.

Adding to complications at the Capitol, the Assembly has sent to Schwarzenegger the primary budget bill but not its tax acceleration, one of about two dozen trailer bills.

The strategy prevents the governor from vetoing both at the same time.

After Wednesday's session with Schwarzenegger, legislative leaders expressed hope that a showdown will not be necessary.

"We'd like to avoid a veto," Bass said. "We'd like to avoid a veto override. Conversations are ongoing."

Call Jim Sanders, Bee Capitol Bureau, (916) 326-5538. Staff writer Peter Hecht contributed to this report.