The state's most crowded race for Congress will be a test of whether President Donald Trump's support in rural Minnesota has frayed.

Seven candidates are competing to fill the First District U.S. House seat left open by the DFL gubernatorial candidacy of Rep. Tim Walz. Regardless of the outcome at Saturday's endorsing conventions, both parties could be headed for primary contests on Aug. 14.

Voters in the district, which stretches along the Iowa border from South Dakota to Wisconsin, narrowly supported Barack Obama in 2008 and 2012, then flipped decisively in 2016 to back Trump over Democrat Hillary Clinton, 53 to 38 percent. Walz defeated Republican Jim Hagedorn, who's running again this year, by just 2,548 votes in 2016.

The seat is on the target lists of both national parties and is rated a tossup by politics handicappers at Cook Political Report, Inside Elections and Sabato's Crystal Ball.

Local party officials think the race is too close to call.

"This probably will live up to the billing as one of the most competitive races in the country," said Aaron Miller, GOP chairman in Olmsted County. "This is by far not a slam dunk for the Republican candidate."

Debra Hogenson, the district's DFL chairwoman, said that Democrats who felt in 2016 that Clinton would win "and their participation wasn't needed" are more energized now. "If our most conservative-leaning areas improve their Democratic vote just a little bit" the DFL can hold the seat, she said.

Seven of the district's 21 counties — Blue Earth, Fillmore, Freeborn, Houston, Mower, Nicollet and Nobles — voted twice for Obama, then supported Trump. That's the territory that could determine the outcome and help decide whether Republicans maintain control of the U.S. House.

The GOP race pits state Sen. Carla Nelson of Rochester against Hagedorn of Blue Earth, a former Treasury Department official who also lost to Walz in 2014. Earlier, he competed for the 2010 Republican endorsement.

Trump's proposed tariffs on China, which would affect soybeans, corn and pork, are a hot topic in the district. Hagedorn blames Obama's health care, regulatory and tax policies for hurting farmers. The Trump administration, he said, "should do everything it can to make sure markets are open."

Nelson said Obama policies and those of DFL Gov. Mark Dayton have added to farm woes. She's "allowing our president a little room for the art of the deal before raising a huge alarm" about trade. She understands "the importance of really holding China accountable," she said.

Hagedorn said he's running "to try to partner with the president." His support isn't based on personality, but he agrees with Trump "pretty much down the line on policies," he said. "People who supported Donald Trump in the last election want him to succeed."

Nelson plans to remain in the race if Hagedorn wins the party endorsement, she said, because she considers it "my duty and my responsibility to make sure the strongest candidate is on the ballot."

Hagedorn collected more than $133,000 in the first three months of 2018. Nelson was close behind with $112,421.

The DFL field includes a former state senator, Vicki Jensen of Owatonna, and four political newcomers.

Dan Feehan, who has led the DFL fundraising race, is — like Walz — a military veteran and former teacher. He was a Pentagon official in the Obama administration. Although Feehan is from Red Wing and lives in North Mankato, his return to Minnesota after years away to run for office has led to criticism. Nelson called him a "career D.C. insider" and said voters prefer someone who "really is a First District person."

Feehan said his campaign reflects "the values I learned growing up here. You put your community above yourself." He's been working to build grass-roots support, in part by participating in service projects in district communities.

Voters, Feehan said, are less focused on Trump than on "practical concerns: Health care is unaffordable, college debt, worry about there not being enough labor jobs, national security."

Rich Wright of Rochester Township is a lawyer and another military veteran. "People are looking for candidates that are authentic and honest, and they're tired of the political climate in Washington," he said. He's focusing on affordable health care coverage, a $15 minimum wage and tapping into Democratic activism ignited by Trump's election.

Wright expects big Democratic wins this fall.

"My concern was that the energy would taper off and then people wouldn't show up," he said. Instead, "it's been more like an avalanche."

Joe Sullivan, who works in the clean energy field and lives in Mankato, shares that optimism. "The DFL base is fired up because of what's happening with Trump and his policies: the rollback … of health care, the environment [and] the lack of investment" in rural infrastructure, he said.

Sullivan has been endorsed by several unions and said his candidacy is fueled by a sense of duty. "We have to step up and say 'not on my watch,' " he said. "If not me, who?"

Jensen said that her legislative experience enables her to "explain not only what I want to do, but things I've already accomplished," particularly in education. She called herself a "passionate pragmatist" and said her background gives her an advantage in dealing with Republican lawmakers.

Reaching out to voters who have supported GOP candidates is vital, Jensen said. "If we don't do that and rely on some blue wave that's coming, I think we run into trouble."

The final DFL candidate is Johnny Akzam, a web marketing developer in Kasson. Akzam said he's talking to voters about economic issues such as a federal job guarantee and plans to compete in the DFL primary. Bob Ries, a retired professor and Navy veteran who lives in Winona, said Wednesday that he is ending his DFL candidacy for medical reasons.

Jim Hepworth, the district's DFL vice chairman, is pleased with the large field.

"They each have their own strength and story," he said. "It's brought a lot of new people in and I think that's a real advantage."

Another DFL asset, he said, is the track record of the president and the GOP-controlled U.S. House. "People are realizing they may not be ready to govern," Hepworth said.

Dennis Schminke, Mower County GOP vice chairman and a two-time state House candidate, said November's outcome in the First District will depend on turnout and the fall race will be "hotly contested"

Beyond that, he's unsure how things will play out. "There is not a day, there is not an hour that I wish Hillary Clinton were president instead of Donald Trump," he said. "Having said that, [Trump] has me scratching my head once in awhile and I have an uncomfortable feeling."

Judy Keen • 612-673-4234