Sen. Elizabeth Warren Elizabeth WarrenHillicon Valley: Subpoenas for Facebook, Google and Twitter on the cards | Wray rebuffs mail-in voting conspiracies | Reps. raise mass surveillance concerns On The Money: Anxious Democrats push for vote on COVID-19 aid | Pelosi, Mnuchin ready to restart talks | Weekly jobless claims increase | Senate treads close to shutdown deadline Democratic senators ask inspector general to investigate IRS use of location tracking service MORE (D-Mass.) is on the rise in the battle for the 2020 Democratic nomination — and that spells trouble for Sen. Bernie Sanders Bernie SandersThe Hill's Campaign Report: Trump faces backlash after not committing to peaceful transition of power Bernie Sanders: 'This is an election between Donald Trump and democracy' The Hill's 12:30 Report: Trump stokes fears over November election outcome MORE (I-Vt.), her main competitor on the left.

Warren’s momentum was underlined by a CNN-Des Moines Register-Mediacom poll in Iowa over the weekend. It showed Warren just a single point behind Sanders, with 15 percent support to his 16 percent. The front-runner, former Vice President Joe Biden Joe BidenPelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Hillicon Valley: Subpoenas for Facebook, Google and Twitter on the cards | Wray rebuffs mail-in voting conspiracies | Reps. raise mass surveillance concerns Fox News poll: Biden ahead of Trump in Nevada, Pennsylvania and Ohio MORE, led the pack with 24 percent support.

ADVERTISEMENT

If Warren were to pull ahead of Sanders, she would become the leading left-wing alternative to Biden — a shift that would fundamentally alter the dynamics of the race.

“She certainly does seem to be taking votes away from him,” said Democratic strategist Julie Roginsky. “It seems as if, as she is rising, he is falling.”

Another Democratic consultant, who asked for anonymity to speak candidly, argued that there were real warning signs for Sanders, who became a hero of the left in 2016, when he gave eventual-nominee Hillary Clinton Hillary Diane Rodham ClintonFox News poll: Biden ahead of Trump in Nevada, Pennsylvania and Ohio Trump, Biden court Black business owners in final election sprint The power of incumbency: How Trump is using the Oval Office to win reelection MORE a much closer race than expected.

The consultant drew attention not just to the weekend’s Iowa poll but also to Sanders’s relatively modest numbers in New Hampshire, where he defeated Clinton by a whopping 22-point margin three years ago.

“What would change the nature of the race would be if the order of that Des Moines Register poll reversed, and it became Biden-Warren-Sanders,” the consultant said. “I think Bernie could really collapse if that happened. If I was inside Bernie’s shop, I would be as panicked about that as I would be about the low numbers in New Hampshire.”

There have been some signs that Sanders’s camp is rattled by Warren’s apparent acceleration. A U.S. News and World Report story published Friday included a quote from an unnamed Sanders adviser asserting, “Warren fundamentally fails a basic threshold question: Can she beat Trump?”

The adviser brought up the controversy over Warren’s claim of Native American ancestry, and her decision to publicize a DNA test which proved she did have at least one such ancestor, though rather distantly.

ADVERTISEMENT

The Sanders adviser described that episode as a “debacle” for Warren and argued that it “just fundamentally killed her.”

No one believes the DNA episode was Warren’s finest hour. But the idea that it was politically fatal seems less plausible by the day.

Warren has proven herself a powerful performer on the stump, where she draws large crowds. Her penchant for detailed plans has resonated to the point that one of her slogans — “Warren has a plan for that” — has broken through in ways that other candidates have not.

The Massachusetts senator has also been helped by strong performances at town hall events; a refusal to do similar events on Fox News; and by calling early and unambiguously for President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE’s impeachment.

At an MSNBC town hall event hosted by Chris Hayes last week, Warren made plain her disagreement with Biden’s support for the Hyde Amendment and segued into a broader defense of abortion rights. Biden reversed his position on Hyde soon afterward.

Roginsky said that Warren “has had moments. And I’m hard-pressed right now to recall right now when Sanders has had moments.”

One of the dangers for Sanders is that his 2020 campaign will feel like a retread of his 2016 effort, whereas Warren is making her first bid for the presidency.

That point tends to irritate Sanders supporters, who argue he is not given credit for his policy ideas as readily as Warren. They also note that he continues to lead her in almost all polls and that his fundraising strength is prodigious — a sign, they say, of grass-roots enthusiasm for his candidacy.

A Sanders spokesperson noted in an email to The Hill that “Senator Sanders respects Senator Warren, and they have worked together on many issues for many years.”

The spokesperson also said Sanders was “gratified to see so many Democratic candidates in 2020 now promoting parts of the agenda that he campaigned on in 2016, and that he has advocated for for his entire life. It is certainly a good thing that Senator Warren is joining with Senator Sanders in campaigning on issues like tuition free college and a Green New Deal.”

Other voices within the party argue that the whole nature of the 2020 campaign, with a huge field, is very different from 2016, when there were only ever five serious candidates, and Sanders was clearly the main challenger to Clinton.

“I don’t think of it as a singularity of Warren-Sanders, one-on-one,” said Democratic strategist Joel Payne. “Four years ago, Bernie Sanders was the only alternative: It was Hillary Clinton or Bernie Sanders. Now, all of the ideas that Bernie Sanders championed, that mantle is also being carried by a half-dozen other people.”

In 2020, Payne added, “You can have the Bernie Sanders ideas without necessarily having Bernie Sanders. He is not the only ‘Option B’ choice.”

Others on the left argued that concerns about a split in the progressive vote were overdone.

Neil Sroka, the communications director of the progressive group Democracy for America, emphasized how long there was to go before the first contests — the Iowa caucuses are not until early February. Even after that point, he noted, voters on the left of the party would still have time to make up their minds as the primary evolved.

“What’s really important about this process is that it is iterative,” Sroka said. “It’s not that there is a single election day where folks have to be worried about splitting the vote.”

For now, he said, progressives could take heart in the “abundance” of choices before them.

Others argued that, in such a large field, there were too many crosscurrents to simply say that the rise of one candidate, such as Warren, axiomatically hurts another, such as Sanders.

“I don’t think it’s as simple as to say Warren and Sanders are sharing the same voters,” said Democratic pollster Paul Maslin.

He argued it was just as plausible that the rise of Warren could hurt other female candidates, such as Sen. Kamala Harris Kamala HarrisHundreds of lawyers from nation's oldest African American sorority join effort to fight voter suppression Biden picks up endorsement from progressive climate group 350 Action 3 reasons why Biden is misreading the politics of court packing MORE (D-Calif.), or a candidate who had previously been enjoying a comparable momentum boost, such as South Bend, Ind., Mayor Pete Buttigieg Pete ButtigiegBillionaire who donated to Trump in 2016 donates to Biden The Hill's Morning Report - Sponsored by Facebook - GOP closes ranks to fill SCOTUS vacancy by November Buttigieg stands in as Pence for Harris's debate practice MORE (D).

Still, Warren is rising at an opportune moment — two weeks before the first Democratic debates kick the race into another gear, and as increasing numbers of voters are tuning in for the first time.

“It feels like, right now, Elizabeth Warren is in pole position in the progressive lane,” said Payne.

The Memo is a reported column by Niall Stanage, primarily focused on Donald Trump’s presidency.