U.S. Rep. Collin Peterson said Friday that he would seek re-election in the Seventh Congressional District, formally setting the stage for what could be one of the most hotly contested House races in the country this year.

“This wasn’t an easy decision for me because our country is so polarized right now, but that’s also why I want to ask the voters of western Minnesota to support me again,” Peterson said in a statement announcing his plans Friday afternoon. “There aren’t many like me left in Congress. Rural Democrats are few and far between and I’m concerned that rural America is getting left behind.”

The 15-term congressman was first elected in 1990 and chairs the House Agriculture Committee. On Friday, he said that in addition to agriculture, he wanted to focus on “helping our rural health care facilities, lowering interest rates on student loan debt, taking care of our veterans, and making sure we have good roads and good broadband access across rural Minnesota.”

Peterson is facing what many analysts judge as his most formidable challenger yet in former Minnesota Lt. Gov. Michelle Fischbach, who landed an endorsement from President Donald Trump earlier this week.

Though Peterson is among the more conservative Democrats in Congress — bucking the party by voting for gun rights and against impeaching Trump — his district has increasingly tilted to the right. Trump won the district by 31 points in 2016.

That calculus, plus Fischbach’s entry into the race last fall, has led experts to judge the race as one of about a dozen “tossup” contests for seats held by Democrats in 2020. Peterson’s is the only Minnesota congressional seat, Democratic or Republican, currently deemed a “tossup” by the Cook Political Report.

Peterson’s chairmanship of the House Agriculture Committee would likely be a pillar of his re-election effort, something Minnesota DFL Party Chairman Ken Martin alluded to in a statement celebrating Peterson’s decision Friday.

“Now more than ever, our farmers need a fighter in their corner, and there’s no better fighter for farmers and for Greater Minnesota than Representative Collin Peterson,” Martin said.

Dave Hughes, a U.S. Air Force veteran from Karlstad, Minn., who unsuccessfully challenged Peterson twice before, is also running. Other challengers are Noel Collis, a gastroenterologist from Albany, Minn.; Joel Novak, an Army veteran from Alexandria; and Jayesun Sherman, a pastor in Windom, Minn.

Peterson’s announcement came nearly two months later than promised. Ahead of Joe Biden’s decisive Super Tuesday victory in Minnesota, Peterson publicly endorsed the former vice president after U.S. Sen. Amy Klobuchar dropped out of the race.

Fischbach’s campaign, and other Republicans closely watching the race, have sought to tie the Blue Dog Democrat to the more progressive agendas of House Speaker Nancy Pelosi and freshmen House members like Ilhan Omar and Alexandria Ocasio-Cortez.

Fischbach was a prized recruit for the National Republican Campaign Committee that U.S. Rep. Tom Emmer, R-Minn., leads. Even before Peterson’s announcement was made official Friday, the committee made a broad appeal to Trump supporters who previously backed Peterson.

“This is definitely a race and this is definitely on our radar,” said Carly Atchison, a spokeswoman for the group. “We’re looking forward to Collin Peterson defending the fact that he voted against President Trump 75% of the time in the district that [Trump] won.”

Fischbach raised $364,000 for the final quarter of 2019 — a record haul for a Republican candidate in an off year. Peterson, by contrast, raised $157,725 amid uncertainty over his electoral future.

Correction: A headline on previous versions of this article misstated how many terms Rep. Collin Peterson has served: He is in 15th term and is seeking a 16th.