I've got to hand it to the writers of American political attack ads. They're masters at amassing information that's sufficiently tethered to the truth to pass legal muster, then manipulating it into a misleading mess.

Today's case in point: the latest attack on Joe Radinovich, DFL candidate for the U.S. House in Minnesota's Eighth District, by the Republican Congressional Leadership Fund.

The ad — like a similar one released last month and popping up ad nauseam on YouTube and cable TV channels — references Radinovich's 14-year record of minor driving violations and, more recently, of allowing parking tickets to pile up while he ran Minneapolis Mayor Jacob Frey's 2017 campaign. He's had 18 parking tickets since 2010 and four speeding tickets since 2009.

That record is presented as "18 crimes, 30 traffic violations" and five driver's license suspensions, all relating to late payments of fines. Parking tickets aren't technically crimes under Minnesota law, a point the Radinovich campaign's attorney made in letters to TV stations last week asking that the ad be pulled from the air. Still, it's close enough to the truth for the first ad to earn an A-minus on KSTP-TV's Truth Test.

What is nowhere close to the truth is the latest ad's conclusion that Radinovich has "spent his life running from the law."

It goes further. With a mysterious image of a foil-contained flame on screen, it intones, "The cops even charged Radinovich with possession of drug paraphernalia."

When Radinovich was 18 and a student at Macalester College, he was pulled over by law enforcement in Crow Wing County for failing to signal a turn. The cops found a marijuana pipe in his car. The result: two petty misdemeanors, both dismissed, though they resulted in one of the driver's license suspensions the ad mentions.

So the ad is true. It's also indecent in the eyes of anyone who's aware of the heavy burden that Radinovich, now 32, carried in his late teens.

As a junior in high school, Radinovich came home one afternoon to the sound of a gunshot and discovered the bleeding body of his younger brother, who had attempted suicide. His fast action likely saved his brother's life. He then missed months of school to stay with his brother while he was hospitalized in the Twin Cities.

A worse blow came almost a year later. While Joe was competing at a Knowledge Bowl meet, his step-grandfather murdered his mother, then killed himself.

Radinovich tried to carry on with the life he'd planned and enrolled in college that fall. But his emotional recovery from those blows was far from over. A dark time followed, he told me last week. Stability finally came when he was back in his hometown after leaving Macalester, employed by the Crosby-Ironton school district and working with a student who had also experienced trauma at home.

Helping others gave him a sense of purpose that propels him still. "More people deal with the types of circumstances I did than we sometimes realize. More people ought to have the type of second chance that I had to realize a better life. I'd like to help make that happen," he said.

Radinovich has made no secret of his family's story, but he doesn't broadcast it, either. When it comes up, he talks about how his experience influenced his record as a single-term legislator and his platform as a candidate for Congress. For example, he says, he favors Medicare for all in part because he knows how much his family needed the health insurance his dad's union electrician job provided. He favored marriage equality as a legislator — knowing many of his constituents disagreed — because he was sensitive to the high suicide rate among LGBTQ young people. "I cared about the gay kids at Crosby-­Ironton," he said.

I'd say those references to his back story are in keeping with what Minnesota voters want and expect from their elected officials — which is the opposite of the use political admeisters make of the histories of those who run for office. Radinovich isn't whining. He sees the pounding he's taking from the Republican ads as a test of character, one he hopes he's passing.

But he's not all that's being tested. Democracy is, too.

Around the country, both parties and their independent-expenditure allies broadcast ads that weaponize the most painful parts of candidates' life stories. Their deployers offer a simple justification: Attack ads work.

They're right. But they work in the same way steroids do in medicine. They can make a patient stronger in the short term. But their long-term use puts the patient at serious risk.

After several decades of a steady election-year diet of attack ads, their damage to democracy is clear. They make politics seem unsavory and mean-spirited. Voter disengagement and low turnout result. They drive an ever-deeper wedge between political parties, fueling the belief that the opposite party is not just wrong, but evil. Extreme polarization and an inability to govern result. They convince people that all politicians are crooks and unsavory characters. Tolerance for truly dangerous personalities results.

Radinovich described the consequences well. "This is what makes people cynical about politics," he said. "It demeans the important work that people do in public service. And a lot of people have said to me, 'This is why I won't run for public office.' "

Awareness of the long-term effects of personal attack ads evidently isn't sufficient to stop them. But voter rejection of them would do the job. And Minnesota would be a fine place for a backlash to start.

Lori Sturdevant is a Star Tribune editorial writer and columnist. She is at lsturdevant@startribune.com.