Democratic Gov. Kate Brown and Republican challenger Knute Buehler, locked in the most expensive gubernatorial race in Oregon history, are pouring most of their money into a form of campaigning that hasn’t changed much in decades: 30-second TV ads.

RELATED: Live Oregon and Washington 2018 midterm election results.

Screenshot from a 30-second TV ad paid for by the "Knute Buehler for Governor" campaign. 

Screenshot from a 30-second TV ad paid for by the “Knute Buehler for Governor” campaign. 

Buehler, a state representative from Bend, has spent more than $8.3 million on broadcast and cable advertising while Brown has spent more than $7.1 million, according to campaign disclosure reports.

All told Buehler has so far spent nearly $15 million this year while Brown has spent $14.3 million.

The two have blasted out their ads 35,000 times on TV so far, according to the Wesleyan Media Project, which tracks political commercials.

“Well, it feels actually great to be able to communicate, to be able to tell the story of the big problems in Oregon,” said Buehler, “… Our advertising dollars have allowed us to make that case very strongly.”

Brown expressed a weariness with the expense of the advertising onslaught.

“If this campaign is about nothing else,” she said, “it is about the time for Oregon to move forward on campaign finance reform.”

“If you want to send a message quickly to a lot of people, then TV is still the best way to do it,” said Travis Ridout, a political science professor at Washington State University who is a co-director of the Wesleyan group.

Although an increasing amount of political advertising is being directed toward the internet, traditional TV still gets the lion’s share of political spending.

Kantar Media, a firm that works with Wesleyan to track advertising, projects that campaigns across the country will spend more than $3.2 billion on broadcast and cable by the time people are done voting on Nov. 6. In contrast, digital spending will total about $600 million in this campaign.

Ridout and other experts say politicians are attracted to broadcast and cable for a number of reasons. For one, older voters are still more apt to stick to traditional TV viewing — and they are also the people most likely to vote.

In fact, many people still see more ads than they might admit. News shows still attract large live audiences and are a favorite for campaigns. Buehler and Brown ads also frequently pop up on quiz and talk shows and even sometimes on afternoon soap operas.

“One reason it can be so powerful is you don’t have to choose to view it,” said Ridout. “It just appears in the commercial break of the show you’re watching.”

Pat McCormick, a Portland political consultant who frequently works for business interests, said that television carries an “extra emotional connection” for viewers by telling mini-narratives that can be pared down to 30 seconds — or even shorter.

McCormick said that broadcast advertising is actually getting more expensive, even though audiences are fracturing among a growing universe of cable channels and streaming services.

He said campaigns have to compete with each other to buy ads on shows that audiences tend to watch live — such as news programs. That drives up prices as the campaigns heat up.

John Tamerlano, president of the Oregon Association of Broadcasters and a former general manager of KATU-TV in Portland, said predictions that broadcast would be overwhelmed by digital competition for advertising dollars have so far not turned out to be the case.

“The amount of dollars coming in grow almost every two years,” he said, “so it must show that these campaigns need broadcasters to get their message out.”

Sinclair Broadcasting Group — KATU’s owner and the nation’s largest chain of local TV stations — sees political advertising as a key source of revenue. The firm generated $199 million in political revenues in 2016 and expected more of the same in 2018. “[P]undits are already predicting a contentious 2018 mid-term election which should bode well for broadcasters,” Sinclair said in its 2016 annual report.

Of course, that contentiousness is producing a bumper crop of negative ads from both the Brown and Buehler campaigns.

Ridout, the Washington State political scientist, said the fact that voters say they are bothered by negative ads doesn’t tend to deter candidates.

“We just remember negative better than we remember positive,” he said. “So even if we don’t like it, the message may stick in our minds.”

Brown and Buehler both insist they are sticking to the issues in their ads — while accusing the other side of getting nasty.

Buehler, an orthopedic surgeon, complained that the governor’s ads take personal shots at him by raising questions about his medical business and his investments.

Screenshot from a 30-second TV ad paid for by the "Kate Brown for Oregon" campaign. 

Screenshot from a 30-second TV ad paid for by the “Kate Brown for Oregon” campaign. 

One Brown ad accuses Buehler of hypocrisy because he invested in a clean energy tax credit as a private citizen and then later criticized that tax program after he became a legislator. The ad places the words “scandalous” and “criminal” under a picture of Buehler.

“I understand it’s a sign of a campaign that realizes that they’re losing the election and pulling out all stops,” Buehler said.

Brown defended the ad as a fair summation of his record. Her own biggest complaint was about ads run by a business-backed group, Priority Oregon, that leveled some of the most slashing attacks of the campaign.

“People were disgusted by those ads,” said Brown.

One ad shows a mother reading a bedtime story to her children that claims, among other things, that “you can sell drugs out of a daycare” under Brown’s leadership. The ad is a reference to revelations in The Oregonian/OregonLive about ties between a marijuana business and a daycare.