If aliens from Mars, or even Arizona, landed in California tomorrow, they would surely be perplexed by many aspects of our state's society. Our peculiar state government would have to be high on the list.

Try explaining, for example, why our financially stressed public schools are hiring bureaucrats to monitor the payroll records of construction companies at the same time that they're sending layoff notices to teachers and other important employees.

But that's the case, and it's about to worsen. Soon, the schools might be required to hire still more monitors and send them into the factories of the companies that produce the stuff that goes into the classrooms the construction companies are building.

If this sounds bizarre, it's not because you've just arrived from another planet. You simply need a refresher course in labor politics, and something called the prevailing wage.

First, know this: The schools are not like the rest of us. If we want to add a room onto our house or remodel the bath, we call around to a few contractors, ask for bids and references, and evaluate the offers. Once convinced we are dealing with a list of reputable firms, we look for the lowest price. We feel no shame in this. We do not ask how much our contractor will pay the carpenter or the plumber. We might even take satisfaction in having negotiated the best possible deal.

Not the government. For decades the cost of public projects has been driven by the prevailing wage law. This edict prevents the bidders from offering their lowest possible price. It requires them to pay what the state determines is the most common local wage to anyone who works on the project.

Viewed in its best light, the law is supposed to prevent big public projects from driving down wage rates in a particular community. If the state builds a bridge or a courthouse or a school, the undertaking draws bidders from far and wide. If the going rate for a plumber in town is $30 an hour, the prevailing wage law keeps the government job from attracting $20 plumbers from three towns away and depressing the local job market.

The law's history is also tinged with a hint of racism. The federal government adopted the first prevailing wage rates to keep firms from using non-union black laborers to win contracts in the heavily organized Northeast.

California's version sets the prevailing wage for dozens of trades according to surveys that determine the most common rate paid in a given area. Thus, even if 20 electricians are paid different rates ranging from $15 an hour to $30, if 10 union electricians get precisely $35.67 an hour, that's the most common -- or prevailing -- wage. No bidder on a public project can pay less, even if he's a self-employed contractor doing the work himself.

Whatever you might think of all this, it's pretty much settled law, and except for a few tweaks here and there, has been for many years. All contractors on public projects must certify that they are paying the prevailing wage. A bricklayer must get $36 an hour, including benefits. A painter, $32.73. A tile setter, $37.15.

Now for the new wrinkles. With the voters poised last year to approve a $13 billion school construction bond measure, the Legislature decided we could no longer take the contractors at their word. A new law requires school districts to monitor the wages paid by the firms they hire to build the schools. Each district now must hire a team of people to cull through each contractor's records every week to be sure that the proper wages are paid.

But that's not all. The state is now considering new regulations that would expand the reach of the prevailing wage law. Under the new rules, the state-mandated wage rates would apply not only to work done on the construction site but to work done off-site if it is intended for the project.

Workers who assemble heating and cooling ducts in a warehouse and then ship them to the school site will have to be paid prevailing wage. And school district officials fear that modular classrooms built in factories also will be subject to the law. This means that the firms doing the work will have to pay their employees one wage for the public project and another for work done on private projects -- and the school districts will have to look over their shoulder all the while.

One Sacramento-area school district, Elk Grove Unified, figures it's already spending about $250,000 to monitor payroll records under the law passed last year, at the same time it is preparing to lay off teachers' aides, janitors and other district personnel. If the proposed regulations take effect, they could drive up the cost of new schools by 6 percent, not counting the cost of hiring still more monitors to keep tabs on distant factories.

The prevailing wage law is suspect enough. Requiring the schools to police their contractors was piling on. Forcing school districts to monitor payroll records at remote factories would be madness.