MINNEAPOLIS (AP) — Republican Michelle Fischbach has upset Democratic U.S. Rep. Collin Peterson, the chairman of the House Agriculture Committee, who was seeking a 16th term.

Fischbach is a conservative former state senator who briefly served as lieutenant governor in 2018 when Tina Smith resigned the seat upon her appointment as a U.S. senator. Fischbach argued during the campaign that Peterson was too close to Democratic House Speaker Nancy Pelosi and other liberals.

Peterson, a conservative Blue Dog Democrat, represents western Minnesota’s heavily agricultural 7th District, which sprawls from the Canadian border almost all the way south to Iowa. He rarely faced serious challenges in his career. But the district has become more Republican over the years, which gave Fischbach an opening.

Peterson, who was first elected in 1990, served as chairman of the House Agriculture Committee from 2007 to 2011 and regained the post after Democrats recaptured the House in the 2018 election. He was instrumental in shaping several farm bills and was a champion of the region’s beet sugar industry. He opposed President Donald Trump’s impeachment but sharply criticized his trade war with China because farmers took much of the brunt. Major farm groups endorsed him.

President Donald Trump carried the 7th District by 31 points in 2016, his biggest margin in any of the 29 House districts held by Democrats that year. Peterson won then by just 4 percentage points.

Fischbach served in the Minnesota Senate from a central Minnesota district for 22 years, including two stints as Senate president. She became lieutenant governor in 2018 as part of an unusual political chess game when Democratic Gov. Mark Dayton appointed Smith following the resignation of Sen. Al Franken.