Malpractice payouts by state. (Jeremy Gower/Diederich Healthcare)

A ballot initiative that would increase the amount of money victims of medical malpractice can receive from doctors will be on California’s November ballot, setting up what could be one of the most expensive political contests in the country.

The measure would increase the limit on pain and suffering damages awarded to victims from $250,000 to $1.1 million and peg future increases to inflation. It would also mandate random drug tests for doctors and require physicians to use a state prescription drug database.

Backers, led by Consumer Watchdog, turned in 840,000 signatures to the Los Angeles County Clerk’s office in March, far more than the 504,000 valid signatures required to gain ballot access. On Thursday, the group said it had qualified for the ballot.

The campaign spent about $2.1 million to collect the necessary signatures. That’s a pittance compared to the amount of money supporters will spend to get the measure passed in November — trial lawyers groups, which would benefit from the higher caps, spend millions of dollars each year on political contributions and lobbying.

There will be no shortage of funds on the opposite side, either. The main campaign committee opposing the measure, funded by doctors and insurance groups, reported nearly $32 million in the bank at the end of March, according to the Sacramento Bee.

Both sides have long histories of backing up their big-spending claims with their checkbooks. The insurance industry spent more than $150 million on lobbying in 2013, according to the Center for Responsive Politics; this election cycle alone, the insurance industry has given federal candidates $13.6 million in campaign contributions, a little less than two-thirds of which went to Republicans.

Trial lawyers spend less on lobbying but more on political contributions. This cycle alone, the Center for Responsive Politics reports lawyers and law firms have donated nearly $29 million to federal candidates, about two-thirds of which went to Democrats.

Doctors and health professionals have spent more than $80 million a year lobbying Congress since the beginning of the Obama administration. This cycle, they have donated about $17 million to federal candidates, with about 60 percent favoring Republicans.

And those are just the federal numbers. In the states, where most insurance and malpractice decisions are made, the three powerful industries are spending tens of millions more to advocate their causes.

Ballot measures have become increasingly expensive in recent years as interest groups wage policy fights on television, rather than in the halls of state capitol buildings. After the presidential contest, the second-most expensive campaign waged in 2012 came in Maryland, where supporters and opponents of a proposal to expand casino gambling spent $95 million.

In 2012, the 186 ballot measures in states around the country drew $934 million in spending, an all-time high, according to the National Institute on Money in State Politics. Nearly half of that money, $455 million, was spent on ballot measures in California alone.