Kamala Harris wins progressive praise amid past friction, as GOP hammers Biden VP choice

The reaction from the two top leaders of the progressive base of the Democratic Party to the naming of Sen. Kamala Harris of California as Joe Biden’s running mate was instant -- and glowing.

“She understands what it takes to stand up for working people, fight for health care for all, and take down the most corrupt administration in history. Let’s get to work and win,” tweeted Sen. Bernie Sanders.

The populist lawmaker from Vermont was Biden’s last remaining rival in the Democratic presidential nomination race before ending his campaign and backing the former vice president in April.

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Sen. Elizabeth Warren of Massachusetts, who was the other progressive standard-bearer in the Democratic presidential primaries, emphasized that “@KamalaHarris will be a great partner to @JoeBiden in making our government a powerful force for good in the fight for social, racial, and economic justice.”

The initial thumbs up from Sanders and Warren as well as a slew of other leaders and organizations on the left was noteworthy. Harris’s law enforcement background caused plenty of tensions with progressives during her unsuccessful bid for the Democratic nomination. Her record as a prosecutor as San Francisco's district attorney and later as California attorney general was scrutinized and criticized by plenty on the left.

Harris, who was a strong supporter of a government-run Medicare-for-all health care system when she launched her White House bid, also took arrows from progressives for her moderating stance on the issue during the course of her presidential campaign.

And on Tuesday, some on the left expressed frustration over the pick: Briahna Joy Gray, who previously served as Sanders' national press secretary and has been an outspoken critic of Biden since her former boss withdrew from the race, invoked Harris' tenure as the California attorney general.

"We are in the midst of the largest protest movement in American history, the subject of which is excessive policing, and the Democratic Party chose a “top cop” and the author of the Joe Biden crime bill to save us from Trump. The contempt for the base is, wow," Gray reacted.

But Mo Elleithee, the founding executive director of Georgetown University's Institute of Politics and Public Service and a Fox News contributor, emphasized that “this is not a pick that’s going to cause major pause among the left.”

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Elleithee pointed to a Georgetown University Battleground national poll conducted last week, which included a question on Harris’ favorability among likely voters. The survey indicated that liberal Democrats, at 76%, had a more favorable view of Harris than moderate to conservative Democrats at 61%.

He highlighted that “her numbers are incredibly high with African American voters, with people who don’t like President Trump, with a lot of the key constituencies of the Democratic base….I think she energizes a base that’s already pretty energized.”

While Democrats enjoyed a kumbaya moment wtih Biden's naming of Harris, who becomes the first Black woman to serve on the ticket of major national political party, President Trump, his re-election campaign and allied groups opened fire on the senator.

Trump campaign senior adviser Katrina Pierson argued that "in her failed attempt at running for president, Kamala Harris gleefully embraced the left’s radical manifesto, calling for trillions of dollars in new taxes and backing Bernie Sanders’ government takeover of health care. She is proof that Joe Biden is an empty shell being filled with the extreme agenda of the radicals on the left.”

TRUMP AND HIS CAMPAIGN BLAST HARRIS AS A 'PHONY' AND 'RADICAL'

And the president tweeted out a video prepared by his campaign that charged Harris is a “phony” and that the Democratic ticket “jointly embrace the radical left.”

Elleithee, a senior spokesman for Hillary Clinton’s 2008 presidential campaign and who later served as communications director for the Democratic National Committee, argued that the Republican line of attack against Harris will fall flat.

“People have been dropping opposition research on her since her name started to surface as a top contender and what our poll shows is that her favorable rating has gone up the past few months,” he said.

The poll indicated Harris’ favorable rating rising 8 points from last autumn, when her presidential campaign was floundering.

But veteran Republican strategist Derek Dufresne disagreed.

"I think that messaging will work," he said. "Middle America -- the moderates and the indepdendents -- are certainly not looking for an adminstration that's going to be beholden to the far left."

Elleithee emphasized that “the first rule of a vice-presidential selection is pick the person you feel is most able and ready to do the job," he said. "The second rule is do no harm.”

He stressed Harris's experience.

"She can step into the role and has far more electoral upside that downside,” he said.

And he added HArris brings the bonus of her prosecutorial talents on the debate stage that grabbed national attention as the senator took down Biden 14 months ago at the first Democratic presidential primary showdown. Elleithee predicted that lots of Democrats “ are relishing to see her on the debate stage” with Vice President Mike Pence.

Fox News' Joseph A. Wulfsohn contributed to this report.