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"Can she make a comeback here?" asked Wall Street Journal columnist Mary Anastasia O'Grady, addressing Sen. Elizabeth Warren's D-Mass., dive in the 2020 presidential primary polls ahead of the final Democratic debate of 2019 on Thursday.

"Her total spending plans are over $130 trillion -- that would triple the federal budget overnight and collapse the U.S. economy. And I think she paid the price for that," said former chairman of the California Republican party Tom Del Beccaro on Fox Nation's "Deep Dive" on Thursday. "She peaked too early. And I don't know if she'll be able to comeback."

In the RealClearPolitics average of national polling, Warren has dropped from first place in early October to third place in December behind former Vice President Joe Biden and Sen. Bernie Sanders, I-Vt.

"Her polling literally peaked the day that she was challenged to come out with how [her health care plan] was going to be paid for," said Fox News contributor Liz Peek, "And it's gone straight downhill when the numbers finally surfaced and they didn't make any sense to most people."

Warren's fall in the RCP polling average accelerated in mid-November, following the release of her "Medicare-for-all" plan, which outlined a proposal costing $52 trillion over the next decade, including $20 trillion in new spending.

At the time, Warren insisted that her plan would not raise taxes on the middle class. “It doesn’t raise taxes on anybody but billionaires,” Warren said on the campaign trail in Dubuque, Iowa. “And you know what? The billionaires can afford it, and I don’t call them middle class.

Those remarks were roundly criticized as unrealistic, even by fellow Democrats. "Her plan would create a new tax on employers of almost $9 trillion that would come out of workers' pockets, a new financial transaction tax that would impact investments held by middle-class Americans, and a new capital gains tax that would affect far more people than she stated tonight," Biden Deputy Campaign Manager and Communications Director Kate Bedingfield said in a statement.

"I think the reason that her polling tanked was not because of 'Medicare-for-all'," said Dr. Jason Nichols, who is a full-time lecturer in the African American Studies Department at the University of Maryland. "It was that she wasn't really on the level with the American people when she's talking about taxation."

"Elizabeth Warren couldn't even say, 'Look, your taxes are going to go up,'" argued Nichols, and he contended that voters saw through that.

"I think she did peaked too early," reiterated former chairman of the California Republican party Tom Del Beccaro, "and the reasons why she is falling are not remedial."

"You can't sit there and lie to the American people about taxes and make a comeback," he concluded. "She turned out to have a glass jaw. She didn't have an ability to rise above a difficult moment. And that's what these primaries are all about, testing the mettle of the candidate. And she hasn't done that."

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