Michelle Fischbach’s challenge to U.S. Rep. Collin Peterson in the Seventh Congressional District sets up what could be the most competitive and closely watched House race in Minnesota, putting in play an increasingly Republican-leaning district that has been in Democratic hands for three decades.

The rural, western Minnesota district went to President Donald Trump by a 31-point margin, making it the most pro-Trump district in the U.S. represented by a Democrat. Peterson, however, runs as a Democrat who opposes abortion, supports gun rights, and presides over the House Agriculture Committee, a crucial assignment in Farm Country.

In a close 2020 presidential contest, the district will likely be one of one or two dozen across the nation that could help decide the balance of power in Congress.

In an interview Tuesday, Fischbach, a former lieutenant governor and state senator from western Minnesota, previewed a campaign that figures to cast Peterson as out of touch with a largely rural constituency that is likely to embrace Trump again in 2020.

“The people out there really want to see Trump succeed and the Trump agenda and not the Pelosi agenda,” Fischbach said, referring to Democratic House Speaker Nancy Pelosi. “We need someone there who is going to really represent the people.”

Peterson, a centrist Blue Dog Democrat known to question leaders of both parties, has seen his winning electoral margins dwindle in recent election cycles. He has not commented publicly on Fischbach’s challenge, which was announced Monday. He has said previously that he would decide in January whether to officially seek a 16th term.

Many political observers, and even some Democratic strategists, believe that without Peterson in the race, the district would almost certainly revert to GOP control, raising the stakes for his decision.

Peterson has long been considered one of his party’s more conservative House members, voting against Democratic priorities such as health care and gun control.

That’s helped him hold his seat even as voters in his district have moved toward Republicans in other races there.

Launching her campaign on Labor Day, Fischbach deployed the president’s strategy of linking all Democratic lawmakers to what Republicans are calling a “socialist agenda” of the party’s far left. She cited Peterson’s votes against Trump priorities such as funding for a border wall with Mexico. She also sought to tie Peterson to the “Squad” of freshmen House members, including Minnesota U.S. Rep. Ilhan Omar, who have been the subject of repeated attacks by the president.

“I understand that [Peterson] is Ag chair and I get that, but the agenda they are pushing there is the liberal Pelosi agenda,” said Fischbach. “He’s voting with the Pelosi agenda and with the Squad agenda most of the time.”

Fischbach’s early policy priorities include stronger border security measures, opposing new gun restrictions and supporting laws limiting abortion. Fischbach’s husband, Scott Fischbach, leads Minnesota Citizens Concerned for Life, which lobbies against abortion. The couple lives in Paynesville.

Peterson, the state’s most senior member of Congress, could not be reached for comment Tuesday. But Minnesota DFL Party Chairman Ken Martin underscored Peterson’s role leading the House Agriculture Committee as an asset to farmers in the district, who Democrats argue are being hurt by the president’s trade war with China. “Now more than ever, rural Minnesotans need a fighter like Collin Peterson in their corner,” Martin said.

“Right now, President Donald Trump is engaged in a reckless trade war that’s devastating Minnesota’s farmers and agricultural economy,” Martin continued.

He added that Fisch­bach or Dave Hughes, who recently announced plans to pursue the GOP nomination for a third time, “would doubtless be another rubber stamp for Donald Trump’s disastrous trade policies that are hurting rural communities and creating serious economic uncertainty for farmers.”

Regardless of the trade battle, Minnesota Republicans see an opportunity to transform the state’s political landscape, which has become a priority for Trump as well in 2020.

In a statement Tuesday, Carly Atchison, spokeswoman for the National Republican Congressional Committee, said Peterson “will have a rough road convincing Minnesotans he’s still the best fit.”

Peterson’s margin of victory in the Seventh District — which stretches from the Northwest Angle of Minnesota down to Pipestone in the southwest — has trended downward in recent elections: He retained his seat in 2018 by 4.5 points over Hughes, which was down from the 5-point margin over Hughes in 2016 and the 8.5 points by which he defeated GOP state Sen. Torrey Westrom in 2014.

Soon after Fischbach’s announcement, Kyle Kondik, managing editor for Larry Sabato’s Crystal Ball at the University of Virginia Center for Politics, tweeted that the Seventh District race, once considered a snoozer, moved from a “leans D” to a tossup. He added that Fischbach is a stronger candidate — “on paper at least” — than Peterson has faced so far.

Elected to the state Senate in 1996, Fischbach became the first woman to be selected Senate president in 2011 and became lieutenant governor for Gov. Mark Dayton, a Democrat, when Tina Smith resigned to fill the U.S. Senate vacancy left by Al Franken in 2018. Former Gov. Tim Pawlenty made Fischbach his running mate in his failed bid for the Republican nomination for governor last summer.