California is the location of what will may become the two most expensive ballot campaigns of this election cycle and one of them is heating up this week. Proposition 46 pits doctors against trial lawyers in a battle over raising the limit on malpractice payouts, a fight that has already raised $61.5 million on both sides.

The vast majority of the money—roughly $56 million, according to Ballotpedia—has been raised by groups opposed to the measure, financed by professional associations and large insurance companies. This week, the group that has raised more than 99 percent of that money is launching its first TV and radio ads in English and Spanish.

The No on 46 campaign launched two 30-second ads: “Risk” for TV, and “Real Story” for radio. The TV ad, embedded below, purports to tell “the real story behind Proposition 46,” arguing that trial lawyers wrote and paid for the measure for financial benefit, a cost which they say will be born by “all of us.”

The measure would raise the cap on noneconomic damages—such as pain and suffering—awarded in malpractice suits from $250,000 to $1.1 million and require drug and alcohol tests of doctors and mandate certain professional penalties should doctors fail the tests.

“Changing the malpractice limits is a more controversial proposal, but requiring doctors to be drug tested is something that’s likely to get a lot of support, so they deliberately stuck that in there to make sure the pot was sweetened,” says Bruce Cain, a Stanford University political science professor.

Four groups have contributed $5 million or slightly more to fight the measure: the California Medical Association Physicians’ Issues Committee, the Cooperative of American Physicians Independent Expenditure Committee, NorCal Mutual Insurance Company and The Doctors Company.

That quartet, along with three other contributors—Kaiser Foundation Health Plan, Inc. ($3 million), California Hospitals Committee on Issues ($2.5 million) and Medical Insurance Exchange of California ($2.5 million)—account for half of all the opposition money raised. It’s not unusual to see such expensive campaigns in the Golden State, says Cain.

“For the last 30 years, we’ve had some examples of big-ticket initiative measures put on by the trial lawyers or the insurance companies or the utility company or hospitals,” he said. “The big interest groups, when they can’t win their battles in the legislature, take their battles to the initiative process.”

Proponents of the measure have only raised about $5 million, with that money largely coming from the professional organization Consumer Attorneys of California, the non-profit progressive group Consumer Watchdog and an array of law firms.

“This is going to pushed by consumer groups, but funded by trial lawyers,” says Thad Kousser, a political science professor at the University of California, San Diego.

More fundraising and spending is expected over the next of couple months on both sides.

Another measure, Proposition 45, has generated $38.5 million in campaign contributions, again largely from the health industry-financed opposition. If approved, it would require government approval of insurance rate changes.

Though it’s not unusual for California to see these sums spent on ballot battles—the two measures combined have already generated $100 million—it’s also still early. Last year’s fight over a Washington state measure that would have required genetically modified food labeling went down as the most expensive in state history thanks to the big-spending opposition, funded by large agribusinesses. More than two-thirds of the millions raised by that opposition campaign hadn’t streamed in until September and October.

UPDATE: This post was modified to make clear that Proposition 46 would alter the cap only on noneconomic damages in medical negligence lawsuits.