On November 8, most eyes will be on the historic presidential contest between Hillary Clinton and Donald Trump. But the pharmaceutical industry will be focusing on another vote: Proposition 61, a California public referendum that could become the first initiative to truly draw blood from drug makers, which have largely refused to change their pricing habits despite an ongoing political firestorm over the issue.

For the reader that has somehow managed to miss the mobs with pitchforks: pharma companies from Pfizer pfe to Mylan myl have drawn outrage for hiking prices—in one case by several thousand percent—on life saving drugs. Trade groups like the Pharmaceutical Research and Manufacturers of America and the Biotechnology Innovation Organization argue that biopharma’s problem isn’t with prices, it’s with communicating the value of its medicines—i.e., it’s more or less a PR issue.

So far, that PR issue hasn’t hit drug makers’ bottom lines. While some companies have been forced to offer lower-priced medications and steeper patient discounts amid tumbling share prices—such as Mylan did for its EpiPen in August after harsh rebukes over the life-saving device’s soaring price—more than two-thirds of the 20 largest pharma firms used price hikes to boost revenues in 2016, according to a Wall Street Journal analysis of first-quarter earnings.

But this year, public perception could take a real toll. Not at the federal level: the pharma industry is confident that federal action on drug prices is highly unlikely during an election year. But the state level is a different question. If California’s measure—which would cap how much state health programs pay for treatments at the deeply discounted level paid by the Department of Veterans Affairs—passes, it could open the floodgates in other states.

The public support for the initiative is not without reservation. Some patient groups have warned the measure could be difficult to implement and might lead drugmakers to actually increase what it charges the VA to offset losses. Still, Prop 61 has enjoyed widespread support in recent polling.

Pharma has taken note. Companies like AbbVie abbv , Pfizer, AstraZeneca, and others have already poured more than $70 million into defeating the initiative—by far the most money being spent on any California referendum this year. For the first time in a while, the rising costs seem to be going ways.

A version of this article appears in the September 15, 2016 issue of Fortune with the headline “Pharma Doesn’t Care About Your Outrage.”