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Despite facing fierce criticism from her supporters, Tea Party hero Sarah Palin isn't backing down from her endorsement of former Hewlett-Packard executive Carly Fiorina in the GOP's U.S. Senate primary in California.

Palin's endorsement surprised and outraged many of her supporters who expected her to pick Tea Party favorite Chuck DeVore.

"The governor is never one to go with the flow," Jason Recher, a spokesman for Palin said, explaining that the former Alaska governor respects the differing opinions but is sticking by her choice. "She is a very independent person, and she shakes things up in establishments -- including grassroots establishments -- all the time."

The former Republican vice presidential candidate made the endorsement on her Facebook page, saying Fiorina's experience running a major corporation is sorely lacking in Washington.

In the Thursday posting, Palin called Fiorina a "Commonsense Conservative" who has the potential to beat "liberal" Democratic Sen. Barbara Boxer in November.

But Eric Odom, chairman of Liberty First PAC, a Tea Party-fueled political action committee, called Palin's endorsement an "unforgivable sin," and her second strike after endorsing her 2008 running mate John McCain in his Senate race.

"This one is much worse, though," Odom wrote on his blog, arguing that Fiorina is not a "commonsense conservative."

"The first strike was painful, but tolerable," he said. "This second strike is downright confusing, dishonest, and leaves me feeling cheated."

Fiorina -- an adviser on the McCain-Palin ticket in 2008 -- is essentially in a two-person race with former congressman Tom Campbell, who is leading in most polls. DeVore is trailing far behind.

More than 7,400 Palin fans clicked the "like" button on the Facebook endorsement, but the snub of DeVore prompted the Facebook outcry.

There is no "dislike" button on Facebook. But scores of the nearly 1,800 comments from Palin's 1.5 million-plus Facebook supporters -- many among the Tea Party faithful -- took the time to plead in Facebook comments for Palin to change her endorsement.

Some called Palin just another typical politician who was losing supporters, while others said they backed her choice and still admired her. Both sentiments also were posted on Palin's Facebook Wall.

Palin later posted an addendum, noting that "some reaction right out of the chute calls for more information."

She listed reasons for her support, including the endorsement of Fiorina by National Right to Life and the California Pro-Life Council.

"She is pro-life, pro-traditional marriage, pro-military and pro-strict border security and against amnesty," Palin wrote. "Carly is also a strong supporter of the Second Amendment. Like me, she is a member of the (National Rifle Association), has a 100 percent NRA rating, and she and her husband are gun owners."

In a debate taped Thursday to be broadcast Sunday, Campbell was the only one of the three GOP candidates to say the ability to buy a gun should be suspended if a citizen's name is placed on the airline "no-fly" list.

Fiorina and DeVore said the list is not dependable for making assessments about Second Amendment rights.

Dawn Wildman, whose San Diego-based Southern California Tax Revolt Coalition has about 2,000 members, said she has been fielding calls and emails from Tea Partiers who feel betrayed by Palin's endorsement.

"My first thought when I heard about the endorsement was, wow, I guess she doesn't plan to run in 2012," Wildman said.

Wildman said there was consensus among her fellow activists when it came to supporting DeVore.

"I think most of us see Palin as a company girl now, meaning the GOP," Wildman said. "For her to endorse Fiorina wasn't terribly shocking. I think what's more interesting is that Palin tries to suggest she aligns herself with the Tea Party movement but is clearly out of touch with what the Tea Party movement is saying in California."

In Fairbanks, Alaska, Tea Partier Rita Heidkamp said she has no personal position on the California endorsement. But it's Palin's choice to make, and no one else's, said Heidkamp, whose group -- the Fairbanks 912 Project -- organized a local Tea Party tax day rally.

"She should endorse whoever she thinks is the best candidate," Heidkamp said. "That's her right and her responsibility."

The Associated Press contributed to this report.