Democratic U.S. Sen. Amy Klobuchar brushed off a challenge from Republican Kurt Bills Tuesday night, decisively winning a second term.

She said her win, which became clear soon after the polls closed, was a tribute to her pragmatic, not partisan, approach to leadership. At press time she had garnered nearly twice as many votes as Bills.

"I want everyone to know that I've been honored and humbled to be your senator and I will continue to be honored and humbled to represent the people of Minnesota," Klobuchar said in her victory speech. She outlined an aggressive plan as she returns to the Senate, one of debt reduction, infrastructure improvement and politics of civility.

"I'm talking about having the decency to treat people with whom you disagree with civility and respect," she said.

Bills said he would return to the Rosemount high school where he has taught throughout his campaign.

"I was in first hour today, I'll be in first hour tomorrow morning. Republicans don't take days off," Bills said. "We are going to win this state down the road."

Klobuchar's cruise to victory in a state known for tight contests could give her more clout in Washington and a fresh look as a possible 2016 presidential candidate. Even before Tuesday, Klobuchar was considered among the most popular lawmakers in the country and often was called upon to stump for other candidates even as she ran her own campaign.

"Somebody who wins that decidedly will be looked at for national office," said Dennis McGrann, a longtime Washington lobbyist at Lockridge Grindal Nauen. "Amy Klobuchar's name is going to have to be front and center."

The senator herself brushes off questions about her future ambitions, which just allows the speculation to flourish.

"Right now I am focused on my job as the senator from Minnesota," Klobuchar said on Monday. "No matter what I do in the Senate, my number one goal is representing Minnesota. ... I love my job."

In her first term, Klobuchar made her mark by voting with Democrats almost all the time but also taking on issues -- from veterans' pay to increasing access to life-saving drugs -- where she could work with Republicans without regard to party.

Her re-election campaign behind her, Klobuchar will be expected to use her new term to tackle thorny issues head on.

She has said when she returns to Washington, she plans to work immediately on economic issues, the federal budget and the size of the debt. If the lame-duck Congress makes no changes, immediate and automatic cuts will go into place in January.

"We need to reduce our debt in a balanced way, with everyone, including the wealthiest, sharing in the solution. ... But the math needs to add up and that means not only cutting spending, it also means revenue," Klobuchar said in her victory speech.

At the Republican victory party, a handful of Bills' interns learned that he had lost the race soon after the polls closed.

"We expected it, though. We were so outspent," said Dylan Mato, 17, of Rosemount. "She was tough to beat."

Despite the loss, Mato said he was glad that the party ran "a true conservative," rather than a moderate, even though it may have widened the gap.

Still, the loss for Bills, a first-term legislator from Rosemount, and the Republican Party will likely mean some GOP soul-searching, which could change the party dynamics going into the 2014 Senate and gubernatorial races.

"I think we have to take a real good look at our endorsement process," said Jennifer DeJournett, a Republican activist who is president of the election-focused VOICES of Conservative Women.

Bills, a freshman state House member, gained his place as the Republican standard bearer with the backing of Ron Paul delegates this spring.

"Ron Paul had more to do with the U.S. Senate endorsement than Kurt Bills did," said former Republican Party chair Tony Sutton. He added that the endorsement need not change but candidates need to do a better job of stepping up.

Better-known and more experienced candidates shied away from the race, waiting until the next cycle when both U.S. Sen. Al Franken and Gov. Mark Dayton will be up for re-election. Both are considered easier targets than Klobuchar ever was.

The party, still regrouping after debts and a massive shakeup, was unable to offer Bills much financial support, and Republican-friendly independent groups gave Minnesota a pass this year.

Since his endorsement, Bills attracted little financial support of his own, no hordes of volunteers and few staff, leaving many Minnesotans wondering who he was. But Bills, a high school economics teacher who kept teaching a morning class throughout the campaign, said he did what he could to spread his message of destructive debt and smaller government across the state.

"I think we worked as hard as we possibly could," said Bills. Thursday afternoon, after a nonpartisan get-out-the-vote rally led by elementary school students, he said he felt "just so blessed to be a part of this."

Maya Rao and Jenna Ross contributed to this report. Rachel E. Stassen-Berger Twitter: @rachelsb