MINNEAPOLIS (AP) — Democratic Rep. Jim Oberstar fell victim to the GOP’s nationwide blitz, losing to upstart Republican Chip Cravaack in an astonishing ouster for an 18-term congressman with a perch atop the powerful House Transportation Committee.

An Oberstar loss seemed unthinkable just a few months ago, but Cravaack built momentum as the election approached by portraying Oberstar as out of touch. With 98 percent of precincts reporting early Wednesday, Cravaack nipped Oberstar by just 4,000 votes out of more than 273,000 cast — less than 2 percentage points.

In TV ads, Cravaack said he ran against Oberstar “with all due respect.” But the former Navy and Northwest Airlines pilot criticized Oberstar for federal spending and supporting the health care overhaul.

Two other incumbents viewed as among the state’s most vulnerable, Republican Rep. Michele Bachmann and Democratic Rep. Tim Walz, held off aggressive challenges.

Walz’s 1st District, which stretches across southern Minnesota from Wisconsin to South Dakota, is a swing district with a recent history of turning out incumbents.

He first rode to office on a Democratic wave by ousting a 12-year incumbent, and said Tuesday night that even in the House minority he would stand up for Democratic values — including opposition to repealing the Democratic health care bill. “It will be over my dead body when that happens,” Walz said.

“If there was a message tonight, it was get it done together, get the solutions that are the best and implement them for the country,” Walz said in his victory speech in Mankato. “We’re willing to reach out our hand and say, let’s fix it for the American public.”

Bachmann easily beat Democrat Tarryl Clark in the suburban Twin Cities-and-St. Cloud-area 6th District, in the most expensive U.S. House race nationwide. And Walz bucked the Republican House takeover, winning a third term in southern Minnesota’s 1st District by beating Republican Randy Demmer.

Oberstar, the dean of the state’s congressional delegation, had never gotten less than 59 percent of the vote since he first ran and won in 1974. He had a long history of bringing largesse to the district even before he became House transportation chairman.

“It’s a miracle what we’ve done,” Cravaack told supporters said during an appearance at his headquarters in Hinckley Tuesday evening, even before returns showed him closing the gap and then overtaking Oberstar.

Oberstar told Minnesota Public Radio he “anticipated a difficult year from the very outset.”

Minnesota’s five other House incumbents, all heavily favored, were re-elected: Democratic Reps. Betty McCollum in St. Paul, Keith Ellison in Minneapolis and Collin Peterson in northwestern Minnesota, and Republican Reps. Erik Paulsen and John Kline, both from the Twin Cities suburbs.

“Your voice was heard overwhelmingly at the ballot box tonight, and the question is, will the politicians in D.C. stand with you or continue to stand for big government and bureaucracy?” Bachmann said in her victory speech at Republican election headquarters in Bloomington. “Any day of the week, I would stand with you. Thank you for letting me stand with you.”

Bachmann and Clark raised more than $15 million between them, mostly by Bachmann, a tea party favorite who cultivated a national base in part through frequent appearances on national cable shows. Clark tried to turn that to an advantage by attacking Bachmann as more concerned with her ambition than her constituent.

Clark’s spokeswoman, Carrie Lucking, attributed the Democratic candidate’s loss in the 6th District to the national wave of Republican winners entering Congress. Lucking said no one expected the Republican “tsumani” that was coming.

In the St. Paul suburb of Woodbury, at the district’s east end, 82-year-old retiree Don Lowry voted for the lightning-rod Bachmann because he likes her style.

“I like Bachmann because she speaks her mind. She has a lot of the same views that I have,” Lowry said. “She’s made quite a name for herself. She speaks up, and that’s good.”