ROCHESTER, Minn. (AP) — Complacency may be the biggest election year challenge for Amy Klobuchar, one of the most popular incumbents in the U.S. Senate, as she runs for a second term representing Minnesota.

The 52-year-old Democrat has raised $5 million so far and is facing off against a little-known opponent, Republican state Rep. Kurt Bills, a high school economics teacher who’s allied with libertarian-leaning presidential contender Ron Paul.

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Democratic party activists enthusiastically endorsed Klobuchar’s re-election bid at their party convention in Rochester on Saturday, taking mere moments to endorse her by acclamation.

Klobuchar worked her way through the Mayo Civic Center hall shaking hands, giving hugs and signing autographs. During an acceptance speech that emphasized her efforts to work across the aisle, she urged party faithful to work hard this year, from knocking on doors and working at phone banks to having a presence on social media.

“Reach out to independents and to Republicans. Find the common ground,” she said. “Because when the choice is so stark as it is in this election, you will find friends and supporters in places you never expected to find them.”

Klobuchar, who won her first Senate race with a commanding 58 percent of the vote, runs the risk of being almost overlooked as Democrats turn their urgency toward winning back a U.S. House seat in northeastern Minnesota and overturning Republican majorities in the state Legislature.

Former Republican Sen. Rudy Boschwitz said Klobuchar’s race isn’t so different from his position in 1990. At this point that year, he was considered a safe bet for re-election. He went on to lose narrowly to a little-known Democratic college professor named Paul Wellstone in a major upset.

Boschwitz said he spoke recently with Bills and told him of the parallels.

“I said, ‘In politics, nothing is for certain,'” Boschwitz said. “The impossible in politics often happens.”

Bills criticized Klobuchar for failing to reduce the national debt and backing economic policies that have “left the average Minnesotan behind.”

“This debt is not going away. It’s getting bigger and unsustainable by the day,” Bills said in a statement. “‘When I write these numbers on the chalk board to teach my students, they can just be erased at the end of the day. However, the real debt is not so easy to deal with.”

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For her part, Klobuchar said she isn’t assuming anything about her re-election. She is spending her weekends campaigning in parades around the state and said she has a highly motivated campaign staff.

Klobuchar is also emphasizing her bipartisan track record and is encouraging partisan Democrats to look outside the party for extra support. She’s worked with Republicans to replace the collapsed Interstate 35W bridge in Minneapolis, secure leave pay for Minnesota National Guard members and approve a new bridge over the St. Croix River near Stillwater.

Some Democrats said they aren’t taking Klobuchar’s re-election for granted, particularly after 18-term U.S. Rep. Jim Oberstar was surprised two years ago in northeastern Minnesota. That’s when Republican Chip Cravaack took advantage of what seemed to be a sleepy race to win what had been a Democratic stronghold.

Meg Litts heads the Mille Lacs County DFL in Cravaack’s district and said she is not relaxing about any races this year.

“For me the election is never over until it’s over,” Litts said. “I think there are many who are starting to feel a much bigger sense of urgency.”

Others said it gets harder to motivate the volunteers who staff phone banks and spend time knocking on doors when a candidate looks well-suited for another win.

“It’s much harder when the candidate is quote-unquote secure,” said Greg Miller, a 57-year-old Democratic activist from Lino Lakes, a northern Twin Cities suburb. “There is no such thing as a safe candidate. There’s so many things that can happen.”

Klobuchar said she has never rested during a campaign, even when running unopposed for re-election as Hennepin County prosecutor. She bought billboards and distributed lawn signs before an easy win.

“You never know,” she said in an interview at the convention. “There could be a write-in.”

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