On June 6, 1978, Californians used a ballot-box megaphone to issue this warning to elected officials: Don't move, keep your hands up, back away from our pocketbooks.

Proposition 13 soared to victory. The tax revolt capped property taxes that seemed to be rising out of control. Millions of voters who were worried about losing their homes went home happy.

Twenty-five years later, supporters say that handcuffing the tax-and-spenders and making property taxes predictable was the best thing that ever happened to California. But talk of changing pieces of Proposition 13 is in the air.

Nobody is suggesting that the landmark measure with its protections for homeowners -- the tax rate capped at 1 percent of a property's purchase price and maximum annual increases in property value of 2 percent -- be tossed out or overhauled; voters would never stand for that. But fueled by the state's current budget crisis, discussion is growing over ways to tweak the tax system.

Lawmakers in Sacramento -- as well as cities, counties and lobbyist groups -- are kicking around a host of possible fixes. There are suggestions that the homeowner exemption be raised. There are proposals to lessen cities' post-Proposition 13 reliance on sales taxes. There are bills to make it easier to pass a transportation sales tax.

Some of the measures simply affect laws that interpret the state constitution and need only a simple majority of the Legislature to pass. Other proposals -- like the transportation sales tax -- require constitutional amendments approved by two-thirds votes of the Senate and Assembly to get on a statewide ballot.

Among the most talked-about ideas: lowering Proposition 13's requirement that a two-thirds ``super-majority'' of voters approve new taxes or increases, and changing the way commercial and industrial property is assessed.

Most face a long road to ever becoming law.

``I don't foresee any fundamental changes to 13 in the coming years, but it's now relatively safe to at least talk about proposals,'' said Santa Clara County Assessor Larry Stone.

Proposition 13 has remained consistently popular among voters, according to polls, and supporters who want to make sure its property-tax rate cap isn't touched have long vowed to fight any attempt to revise it.

Splitting the tax roll

But in Sacramento, more than 10 proposals would lessen the super-majority requirement or affect Proposition 13 in other ways. One likely to face opposition from the business community is ACA 16, a constitutional amendment that would leave residential tax protection in place but subject commercial and industrial properties to annual reassessments to full market value.

``This would resolve the problem of the biggest loophole in the state's tax system,'' said the bill's author, Assemblywoman Loni Hancock, D-Berkeley. ``Over time, commercial and industrial property owners have paid less and less of their share of the state's property taxes. It's certainly an unintended consequence of Prop. 13 that homeowners would have to pay a greater and greater percentage.''

It's not the first time such a bill has come up for consideration; in 2000, Assemblyman John Dutra, D-Fremont, introduced but later dropped a split-roll proposal.

Hancock's bill gets its first hearing June 23 before the Assembly Revenue and Taxation Committee. Hancock admits she faces a struggle getting her Republican colleagues behind the bill. ``I hope it'll go from committee and reach the floor,'' she said, ``but June 23 is just the beginning.''

Senate approach

A similar bill, SB 17, sponsored by Sen. Martha Escutia D-Norwalk, would require publicly traded companies to notify the state of a change of ownership. Already passed by the Senate, SB 17 would help governments know when they could reassess a company's commercial building, probably increasing the property taxes in the process.

In a statement, Escutia pointed out that under Proposition 13, residential properties are assessed at full market value whenever they are sold. ``Certain corporate properties, however, change ownership on a regular basis and avoid having their property ever reassessed,'' she said. ``We are losing billions of dollars through loopholes in our corporate property tax code that we need now more than ever for our schools and local communities.''

The business lobby is braced to battle most of these measures. ``We have a stagnant economy in this state and we need to do things to get it going, not make it worse,'' said Bill Hauck of the California Business Roundtable, which opposes annual reassessments for commercial property and any attempt to weaken the super-majority rule.

Carl Guardino, chief executive of the Silicon Valley Manufacturing Group, said, ``We hear SB 17 is on life support and someone should pull the plug.''

Lower threshold

However, his members do support ACA 4, a constitutional amendment introduced by Assemblyman Joe Simitian, D-Palo Alto, that would lower to 55 percent, from two-thirds, the vote needed to raise parcel taxes for schools and community college districts.

``The idea of taxes and fees is so ideologically polarizing,'' Simitian said, ``that it's tough for even my moderate Republican colleagues to come on board. But if we can't make this happen in the Legislature, we'll start talking about whether there's support for a ballot initiative.''

Freshman Assemblyman Guy Houston, R-Livermore, said, ``I don't think they'll get the Republican votes and I doubt they'll have all the Democrats, either. I don't see any changes anytime soon for Prop. 13.''

What's significant this year is the willingness in Sacramento to discuss changing Proposition 13. ``It took 20 years to even utter the words `split roll' without getting killed,'' said Joel Bellman, spokesman for Los Angeles County Supervisor Zev Yaroslavsky, referring to the proposal to treat residential and commercial property differently.

Years of protection

Even the 200,000-member Howard Jarvis Taxpayers Association says it is neutral on the idea of a split roll. President Jon Coupal said, ``We want to send a signal to the business community that they'd better stop supporting tax-increase proposals, or we'll have no choice but to embrace the split roll to protect homeowners.''

No matter what ideas rise to the top of the heap, any constitutional change to Proposition 13 will have to pass muster with voters such as Yvonne Holcomb, 69, a Palo Alto homeowner on a fixed income.

``All I have is this house,'' Holcomb said. ``I have to live within my means, even though I do live in Palo Alto. So when I think of Prop. 13, I think of the protection it has given me all these years.''