The late Bill Greene, who chaired the state Senate Labor Committee in the 1980s, once portrayed the politics of workers' compensation in brutally simple terms: "There are four interest groups, and when three get together, they screw the fourth."

That's pretty much how workers' comp, the system that's supposed to support and treat workers with job-related injuries and illnesses, developed into a nearly $30 billion-a-year monster -- more than double what it was just five years ago -- whose reform Gov. Arnold Schwarzenegger ranks as his highest nonbudget priority.

Schwarzenegger often cited workers' comp reform during his campaign for governor, highlighted it again in his inaugural address, and last week, in his first State of the State speech to the Legislature, ramped up the pressure, saying the system's "high costs are driving away jobs and businesses."

"I call on the legislators to deliver real workers' comp reform to my desk by March 1st," Schwarzenegger said bluntly. "Modest reform is not enough. If modest reform is all that lands on my desk, I am prepared to take my workers' comp solution directly to the people, and I will put it on the ballot in November."

There's absolutely no chance that an overhaul of the massively complex workers' comp system will be enacted by March 1. It would be a miracle if anything significant enough to please Schwarzenegger were enacted by the Legislature's adjournment eight months hence, especially since what he wants is bitterly opposed by two interest groups with close ties to majority Democrats: labor unions and attorneys who represent workers' comp applicants.

The workers' comp imbroglio predates Schwarzenegger's governorship by decades. The four interests Greene cited -- unions, attorneys, insurers and employers -- have doubled, thus complicating the politics, but his basic formula still holds true. Last year, with employers screaming about rapidly rising workers' comp premiums, the Legislature enacted a modest reform package that stuck it to the factions considered to be the politically weakest: providers of medical and rehabilitation services.

Those involved in the system are still arguing over the real-world effect of last year's package, with advocates saying premiums should be lowered by billions of dollars but insurers largely unwilling to comply and employers saying the reforms didn't go far enough. And now the latter have Schwarzenegger on their side.

The governor's measure, which was introduced in both legislative houses just two days after his Nov. 17 inaugural, contains dozens of provisions and is aimed at squeezing $11 billion from the system and bringing the state's workers' comp costs, now the highest in the nation, down to the national average. And to have that great an impact, his bill would attack what most workers' comp insiders consider to be the costly heart of the system: permanent partial disability, or PPD.

Workers' comp handles only a few totally disabled workers, and by their nature the temporarily disabled are in and out of the system quickly and cheaply. The big bucks are in the many thousands of workers deemed to be partially, but permanently, disabled due to job-related causes. Their payments and treatments go on for years, perhaps decades, and cost the system many billions of dollars.

Workers' comp lawyers see PPD as their bedrock business, as do medical care and rehabilitation providers, while employers and insurers see it as an expensive game in which too many people are paid for disabilities that are either contrived or exaggerated by those with financial stakes in the outcome. Proposals to sharply tighten up who can claim PPD are the most controversial simply because they involve the most money.

The propaganda war over workers' comp is heating up in anticipation of a showdown in the Legislature, and the strong possibility that it will spill over into a ballot measure battle in the fall. While Schwarzenegger and his allies cite the adverse impact of workers' comp costs on job creation, the other side faults insurers for not reducing premiums after last year's reform.

Like many complex political battles, the clash over workers' comp may hinge on how successful the combatants may be in creating simplistic voter appeals.