But this summer, Proposition 98, the law that guarantees public schools roughly 40 percent of general fund revenue, is being tested like few times before. In the final stages of the weeks-long negotiations over the state's $26.3 billion budget gap, what to do about Proposition 98 has emerged as among the last, and toughest, issues. Gov. Arnold Schwarzenegger has talked of suspending the law and has reopened a battle with Proposition 98's guardian and protector, the powerful California Teacher's Association. Both sides for the past week have waged war over the airwaves, with dueling TV commercials typically not seen in a nonelection year. The governor and Republicans have rejected Democratic calls for new taxes on oil or tobacco. With no added taxes, cuts to schools are among the last ways the state can balance its books. The unpopularity of such cuts guarantees a difficult negotiation. But the talks over Proposition 98 have been made even more complex by lingering suspicions both sides have of the other's motives. Democrats concede they can't avoid more cuts to schools but want assurances that money being carved from school budgets will be restored in future years as the economy recovers. The exact amount of cuts from schools is uncertain, but education officials say there will be more teacher layoffs, more kids stuffed into classes, fewer librarians and counselors and reductions in art, music and gym classes. 'For us, it's been worse than the Great Depression,' said Lisa Kaplan, a Sacramento political consultant and a trustee at the suburban Natomas Unified School District, which has endured steeper funding cuts than during the early 1930s. Proposition 98 and Proposition 13 -- one a touchstone for liberals, the other for conservatives -- are the enduring benchmarks of California's initiative wars. In a state that has seen ballot measures win and lose but mostly disappear from memory like sandcastles at high tide, 'they're the twin pillars of political sanctity,' said Dan Schnur, executive director of the Jesse M. Unruh Institute of Politics at the University of Southern California. 'Propositions 13 and 98 are the two big prizes in a giant political game of capture the flag.' Proposition 13, passed in 1978, restricted property taxes and required a two-thirds vote for tax increases, thereby limiting money for schools and other government programs. Proposition 98, passed 10 years later, was the response, backed by teachers and education groups. It wrote into the state Constitution a complex formula which sets a floor below which school spending is not allowed to drop. But unlike Proposition 13, Proposition 98 can be suspended by a two-thirds vote of the Legislature. The state has done so twice during economic slumps -- in the early 1990s as California's aerospace industry declined and earlier this decade as tax revenue tanked after the dot-com bust. In both cases, the suspension came with at least tacit approval from the teachers union, which has deep pockets, a militia of more than 300,000 members to call on and a proven track record of making or breaking political careers. In the Capitol, the union is among the most effective lobbying forces, a constant presence in every education battle. 'Protecting the integrity of Proposition 98 is definitely a top priority,' said Becky Zoglman, a CTA spokeswoman. The union's power was on full display after Schwarzenegger negotiated the last suspension of Proposition 98 during the down economy of 2004. At the time, negotiators refrained from even calling the move a suspension for fear of riling the union. Instead, they dubbed it 'rebenching.' (Begin optional trim) 'Around here, suspension is a dirty word,' said John Mockler, the longtime education consultant who wrote Proposition 98. 'People just get into the spin and avoid telling the truth. They know it's a bad vote. They can slash here and slash there but can always say they didn't suspend Proposition 98.' (End optional trim) The next year, as the economy recovered, the union grumbled that the governor had gone back on his word to restore the cuts -- and Schwarzenegger paid dearly. The teachers were a key force in defeating ballot measures championed by the governor in 2005. A year later the CTA won a multi-billion-dollar lawsuit settlement requiring the state to pay back education money diverted during the downturn. This time around, Schwarzenegger has publicly maintained that he wants to repay schools whatever money they lose during the current economic crisis. Democrats want payback assurances written into the budget package. They also want guarantees that schools would be repaid if they lose money in future downturns. Schwarzenegger has balked at that. Education leaders believe they've already paid dearly. In the budget signed by Schwarzenegger in February, they say, 60 percent of the cuts hit schools. Those reductions amounted to a cut of 12 percent per pupil, said Robin Swanson, spokeswoman for the Education Coalition, which represents 2.5 million teachers, parents, administrators and school board members. 'It's as if they see education funding as a giant piggy bank that they can raid.' Education officials worry that an outright suspension of Proposition 98 could mean deeper reductions if the economy continues to sour. 'It could open up a Pandora's box,' said Assemblywoman Julia Brownley, D-Santa Monica. Republican officials, meanwhile, acknowledge they'd love to see Proposition 98 simply go away, but understand the political dynamics. Education is a top priority in public opinion polls, and Republicans don't want to be singled out for making cuts -- nor do they want to take on the union. But they also sense an opening. 'The CTA is doing what they always do -- protecting a two-decade-old political investment and franchise,' said Rob Stutzman, a GOP consultant. Tampering with Proposition 98 over CTA's objection 'would set a dangerous precedent,' he added. 'But the sands are shifting on them. Sooner or later, CTA is going to lose one of these Prop. 98 fights.' 