(CNN) -- Alaska Sen. Lisa Murkowski, who lost in the Republican primary last month, says she will launch a write-in campaign to retain her senate seat.
"Today, my friends, my campaign for Alaska begins," Murkowski told a room full of supporters in Anchorage on Friday.
"My heart is Alaska, and I cannot leave you. I cannot stop what we have started," the Republican senator added.
Murkowski also called on thousands of Alaskans who did not vote in the primary to join her renewed campaign.
"It's a futile effort on her part, it really is," former Alaska Gov. Sarah Palin told reporters Friday in Des Moines, in between signing copies of her book for fans after a high-profile speech to the Iowa Republican Party.
"She certainly has the right to do so, but Joe Miller is the right person to lead the state and this country," added Palin, who backed Miller, a one-time long shot and attorney with a sizable bank of Tea Party credentials. Miller is now considered the favorite in the November general election against Scott McAdams, the Democratic nominee and mayor of Sitka, Alaska.
Tea Party Express Chairwoman Amy Kremer, whose group campaigned heavily for Murkowski's primary opponent -- and eventual primary winner -- Miller, said the senator's decision proves she doesn't "get it."
"She was fired by the people. The people were given a choice and they voted for somebody else," she said, adding that she was shocked to learn of Murkowski's decision.
Murkowski, whose write-in campaign could change the tenor of the race, but not if Kremer has anything to do with it. Her group worked hard to push Miller across the finish line, endorsing him in June, sending people to scour the state in his support and spending nearly $600,000 to help his campaign.
Kremer said the Tea Party Express thought it was done with Miller's campaign and that he would be a shoo-in in November. Murkowski's decision changes things.
"Oh, I'm sure we'll be back up there at some point," she said.
Brian Walsh, spokesman for the National Republican Senatorial Committee, on Thursday urged Murkowski -- part of a political dynasty in Alaska -- to back Miller.
"Alaska's voters have spoken, and have chosen Joe Miller as their Republican U.S. Senate nominee," he said in a statement. "If Senator Murkowski is truly committed to doing 'what is right' for her state, then we hope that she will step forward and fully endorse Joe Miller's candidacy."
Murkowski's refusal to bow out of the race could help McAdams' candidacy if it splits the Republican vote. It's happened before. After losing the Democratic primary in 2006, Connecticut Sen. Joe Lieberman announced he would seek to keep his seat as an Independent. The gambit worked, and the 2000 Democratic vice presidential candidate returned to the Senate.
But write-ins are almost never successful. In fact, only one senator has ever been elected as a write-in candidate -- South Carolina Democrat Strom Thurmond in 1954. Thurmond entered the race after the party's state executive committee designated a nominee to replace Sen. Burnet Maybank, a two-term senator who died shortly after winning the nomination to seek a third term.
Thurmond capitalized on voter outrage about the process and won the election with 63 percent of the vote. Thurmond, who later switched parties, was the longest-serving senator in history when he retired at 100 in 2003. Robert Byrd of West Virginia later surpassed that record.
Kremer said she's not worried about Murkowski's decision.
"If anything, it's going to turn more voters out for [Miller] because it's going to tick people off," she said.
Some of those voter may be already ticked off. In her Wednesday release saying she would announce a decision Friday, Murkowski wrote that she believed "the Alaska Republican Party was hijacked by the Tea Party Express, an outside extremist group."
Kremer was unfazed by the criticism.
"She can say whatever she wants to about us," said Kremer. "It's not us who voted. It's the people of Alaska, and I don't think they're too extreme."
CNN's Shannon Travis and John King contributed to this report.