U.S. Sen. Lisa Murkowski on Tuesday evening ended her bid for the GOP nomination to the seat she has held since her father passed it on to her eight years ago.

After elections officials spent the day counting about 13,000 absentee, questioned and early ballots that saw Murkowski make up little ground against Fairbanks lawyer Joe Miller, Alaska's senior senator called Miller and conceded: He had beat the popular incumbent in what national political experts were calling "the most shocking" upset of the 2010 political season.

"It's been a terrible week," a surprisingly upbeat Murkowski said at a press conference held to announce her concession. "I don't see a scenario where the primary will turn out in my favor."

Murkowski's speech Tuesday evening was punctuated by cheers and cries of "yeah" from supporters gathered to witness the senator's swan song.

Outside Alaska, political experts watched closely as the Miller-Murkowski race unfolded.

"This is every incumbent's nightmare," veteran political analyst Larry Sabato said. "They think they're way ahead but come election night they find out differently."

While Sabato and other experts debate whether Murkowski's defeat is indicative of a national trend (they say no), whether inadequate polling played a role in the primary's outcome (they say yes) and whether the senator will pursue a write-in campaign (they're in disagreement), in Alaska, some are ruing the loss of what seniority the state had in the Senate, particularly after Sen. Ted Stevens lost re-election to now-Sen. Mark Begich in 2008.

"It's a shame to lose all that seniority," said former state Sen. Clem Tillion, a Halibut Cove Republican. "Now we have two freshmen down there with no seniority. We're going to be naked."

Murkowski was appointed to the Senate in 2002 when her father, Frank Murkowski, resigned to become governor of Alaska. In the years that followed, she gained enough prominence in the GOP political hierarchy to become ranking member on the Senate Energy Committee, a position that is important to a state that depends on oil and gas production for most of its income.

By 5 p.m. Tuesday, Murkowski still trailed Miller by 1,496 votes -- 49.40 percent to his 50.60 percent. As expected, she gained some ground in Anchorage but not enough to significantly close the distance with Miller, who continued to remain strong in Fairbanks and the Valley. "We did the math. We didn't want this to draw out any longer than it needed to be," Murkowski spokesman Steve Wackowski said.

Miller now faces Democrat Scott McAdams, a former commercial fisherman who is currently the mayor of Sitka, in the Nov. 2 general election.

McAdams issued a brief statement Tuesday night, applauding Murkowski and slamming Miller for running such a nasty race against her. "Lisa Murkowski served Alaska as a state legislator and United States Senator with energy and enthusiasm. We agree on the great majority of Alaskan issues. Lisa Murkowski is a class act who always put Alaska first," McAdams said.

"By contrast, lawyer Joe Miller ran an unfair, nasty campaign that didn't extend to Lisa Murkowski the respect she deserves. Over the next two months, Alaskans will clearly see the difference between Mr. Miller and me, and it starts with basic decency."

Robert Campbell, Miller's campaign manager, tried his best to tone down the rhetoric that had marked the waning days of the campaign. "I don't have anything negative to say about Sen. Murkowski except that she is not Joe Miller," he said. "Joe Miller is just a better candidate."