In Minnesota's Third Congressional District, things have changed

Presidential politics is casting a long, strange shadow on this state this year. Today's case in point: the DFL candidacies past and present of Terri Bonoff in the Third Congressional District, the tony southwest suburban territory that has sent a Republican to Congress in every election for the past 56 years.

Bonoff jolted expectations last weekend when she announced that she would leave the state Senate this year and run instead for the U.S. House seat held since 2008 by Republican Erik Paulsen.

The move was surprising for several reasons. Four-term incumbent congressmen in reliably Republican districts seldom attract opponents of Bonoff's caliber. When they do, it's generally in the wake of a serious misstep or other evidence that the incumbent is falling from favor. Paulsen has made no such stumble; he won re-election in 2014 with 62 percent of the vote.

What's more, Bonoff seemed to be thriving in the Legislature representing Minnetonka and Plymouth. At age 58 and serving her 11th year, she's respected as a rare pro-business DFLer, willing to occasionally vote no on a tax increase or against the wishes of Education Minnesota. She's passionate about her work as chair of the Senate higher-education funding panel. Her effort to bring a German-style blend of work and study to Minnesota higher education is newly launched and was featured last November in Forbes magazine.

Besides, she has already been close enough to the congressional flame to be burned. Bonoff ran for DFL endorsement in the Third in 2008, when the seat was vacated by U.S. Rep. Jim Ramstad after nine terms.

It was the year of Barack Obama — and though Bonoff was among the early backers of the then-senator from Illinois, a former corporate exec and mom of four from Minnetonka was a tough sell to a pro-Obama DFL crowd. Youth, ethnic diversity and liberal orthodoxy were in vogue. The DFL convention spurned her for a smooth-talking, 30-year-old military vet named Ashwin Madia, who turned out to be not as fascinating to general election voters as he was to DFL delegates. Madia netted 40 percent of the vote in his loss to Paulsen, then a state representative from Eden Prairie.

Tastes in presidential candidates have changed since 2008, and evidently, the DFL Third has moved with them. The presidential also-ran of 2008, Hillary Clinton, is the front-runner of 2016. And while Minnesota DFL caucusgoers in every congressional district went for Bernie Sanders over Clinton on March 1, the district in which Clinton came closest to a win was the Third. DFLers there seem to have warmed to female candidates of maturity who are at least on speaking terms with businessfolk.

Meanwhile, Bonoff's focus turned toward national matters. Her husband took a leadership post last year at an airline with international reach, Delta. She became an early and active participant in No Labels, a national bipartisan movement to mobilize the political center. She signed onto Clinton's campaign committee of elected officials.

And the raw partisan meat served up by Republican presidential candidates this spring increasingly worried and offended her, she related last week.

"I was tired of sitting on my couch and yelling at the TV. Literally, I'd get fixated on those darned debates and say, 'Oh, my gosh, what are they thinking?' Watching the violence at a [Donald Trump] political rally and having the presidential candidate defend it rather than quell it, I was inspired."

She had been called with some frequency over the years by the Democratic Congressional Campaign Committee (DCCC) and asked whether she would consider another run in the Third. Each time previously, the answer was no. When one last-ditch call came on April 7, her answer was different.

"I hadn't even looked at Congress since '08. But suddenly I was clear — I want to do this. I want to give it everything I've got. Now is the time to bring my independent style of nonpartisan governance to the conversation."

Bonoff's style is apparently in style in Hillary Clinton's year. The only other DFLer in the race, lobbyist Jon Tollefson, quickly exited and endorsed Bonoff the day she announced her candidacy. State DFL Chair Ken Martin issued an almost giddy statement welcoming Bonoff to the race.

Bonoff would not share any poll results that might have influenced her move. But the DCCC surely gave her a preview of the jaw-dropping results from a March 22-24 poll it released last week to everyone else: In historically Republican MN CD3, Republican presidential front-runner Donald Trump trailed Hillary Clinton by 22 points, 24 percent to 46 percent.

That's bad news for every west-suburban Republican on the 2016 ballot. For Paulsen, the DCCC had more: Against a nameless generic DFL candidate, he polled just 38 percent, compared with 30 percent for the Democrat and 32 percent undecided.

And Bonoff is by no means a nameless generic DFLer.

Still, Paulsen enjoys multiple advantages in their contest. He's got eight years of positive constituent service and a fat $2.3 million campaign war chest to his credit. Bonoff herself is quick to praise him for his leading role in the repeal of the medical device tax that helped pay for Obamacare, and for his advocacy in combating sex trafficking.

But the Trump candidacy is like an earthquake rumbling through American politics, shaking the status quo. It may shift some blue-collar Democratic districts into the Republican column. (Keep an eye on the Minnesota Eighth.) And it has the potential to push some better-educated, better-heeled GOP suburban districts around the country into the Democratic column. That will be especially true if the DCCC's candidate courtship is going as well elsewhere as it did in the Minnesota Third.

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