Her win is a warning flare about the volatility of the primary season. | AP Photo/Lincoln Journal Star Neb. Senate stunner: Fischer wins

Nebraska state Sen. Deb Fischer wrested the Republican nomination for U.S. Senate from Attorney General Jon Bruning Tuesday night, riding a burst of late momentum to pull off an unexpected victory.

Her stunning come-from-behind performance amounts to a warning flare about the volatility of the primary season and the unintended impact of outside groups.


Fischer, a rancher and little-known state lawmaker, maintained a positive, above-the-fray tone while Bruning and state Treasurer Don Stenberg consistently traded blistering barbs. But she also benefited from a flurry of outside spending against Bruning, the front-running establishment favorite for more than a year who watched his polling lead evaporate during the final week of the campaign.

The victory sends Fischer to the general election as a favorite over former Sen. Bob Kerrey, who easily disposed of four lesser-known opponents for a shot at the open seat being left vacant by retiring Sen. Ben Nelson. Nebraska is a must-win for Republicans if they are to acquire the four pickups necessary to flip control of the Senate this fall.

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Democrats argued that Fischer’s surprising win provides with them a better chance at holding the seat, mainly because she’s largely untested and undefined. But public polling taken ahead of the primary has shown Fischer defeating Kerrey by double digits. Republicans outnumber Democrats by about 170,000 and presumptive nominee Mitt Romney is expected to rout President Barack Obama in the state.

Romney also cruised to a primary win Tuesday night — rolling up three-quarters of the vote — but the state’s 32 delegates will actually be selected at the state convention in July.

( See also: 10 facts about Deb Fischer)

Until last week, the Senate contest had been mostly a sleepy affair, with Bruning holding a double-digit polling lead over his two nearest rivals for months.

Outside groups like the Club for Growth and Jim DeMint’s Senate Conservative Fund began chipping away at Bruning’s favorability through a string of hard-hitting attack ads, with the goal of boosting Stenberg.

But the unintended effect was lifting Fischer, a poorly funded candidate who managed to stay out of the mud.

Following the release of her own internal poll showing her surging, Fischer scored endorsements from Sarah and Todd Palin and Rep. Jeff Fortenberry.

Then came the dagger for Bruning.

A brutal $200,000 weekend television ad flight paid for by TD Ameritrade founder and Chicago Cubs co-owner Joe Ricketts that revisited Bruning’s questionable financial interests and cast a cloud over his character.

The closing poll of the race — taken Monday by Public Policy Polling — showed Fischer surging into the lead by 4 points. With 80 percent of precincts counted, Fischer was holding a 4-point advantage over Bruning after he held a similar lead earlier in the night.

Stenberg, who was making his fourth try for a Senate seat, lagged in third place.

Fischer’s victory comes just a week after another unlikely insurgent — Indiana state Treasurer Richard Mourdock — ended the 36-year Senate career of Dick Lugar.

While her victory can’t be claimed by outside groups, it will stoke further anti-establishment fear among front-runners sitting on seemingly comfortable polling leads.

Further downballot, all three Nebraska congressional incumbents easily won re-nomination Tuesday.

GOP Rep. Lee Terry, a seven-term incumbent, fended off a handful of opponents, including former University of Nebraska football player Brett Lindstrom, with a little more than 60 percent of the vote.

All House incumbents running in Oregon, Idaho, and Nebraska skated to primary wins over underfunded and lesser-known opponents.

Idaho Rep. Mike Simpson defeated Chick Heileson, a tea party activist who unsuccessfully challenged Simpson in 2010 and was seeking a rematch.

Romney also scored an easy win in the Oregon GOP primary.

Alex Isenstadt contributed to this report.