Is Elizabeth Warren losing momentum ahead of Iowa caucuses?

Elizabeth Warren is fighting to regain momentum in the turbulent fight for the Democratic presidential nomination amid lingering questions about her authenticity and electability.

Sen. Elizabeth Warren was considered a leader in the crowded race through the fall, yet just seven days before Iowa's first-in-the-nation caucuses, allies, adversaries, and new polling suggest that progressive rival Bernie Sanders has a slight advantage – at least in the battle for the party's left wing. That is just as establishment-minded Democrats begin to rally behind former Vice President Joe Biden, who has tried to stoke fears about his more liberal rivals' ability to defeat President Donald Trump this fall.

Ms. Warren's uncertain status raises questions about whether any female candidate will emerge from Iowa's Feb. 3 caucuses with the political strength to go deep into the primary season, a challenge that will almost certainly require early victories to generate the energy and campaign cash needed to continue.

As would-be supporters acknowledged concern over the weekend, Ms. Warren ignored the shifting political currents and vowed to continue fighting for the kind of transformational change she has championed for months, even while pressing her final case in Iowa before being forced back to Washington for President Donald Trump's impeachment trial.

"Since I first got in this race a year ago, I have not focused on polls. And that's exactly how I'm going to continue to run this race," she told reporters when pressed about whether she needs to change her strategy.

She added: "I'm running a campaign from the heart. That's what it's all about to me. This is who I am."

The people paid to focus on politics on Ms. Warren's team insist they're not worried, and with one week before voting begins, there are no plans to shake up her strategy. The campaign noted that she has already attracted more than 3 million individual donations and assembled a paid campaign operation in 31 states.

The Massachusetts senator got a much-needed boost over the weekend by winning the endorsement of Iowa's largest newspaper. And while she has won a series of coveted newspaper endorsements, Ms. Warren has yet to earn the backing of a single member of Congress from Iowa or New Hampshire, the states that host the first two voting contests.

The shutout particularly stings given Ms. Warren's proximity to New Hampshire, whose two female senators have so far declined to support their neighbor, who has increasingly evoked her gender as a strength on the campaign trail.

New Hampshire Sen. Maggie Hassan is unlikely to support Ms. Warren and is instead considering whether to endorse longtime political ally Mr. Biden, if anyone, according to Democrats familiar with her thinking who were not authorized to share internal discussions. New Hampshire's other senator, Jeanne Shaheen, is facing re-election this fall and is not expected to endorse anyone.

Meanwhile, Mr. Biden was campaigning alongside his newest high-profile female supporter, Iowa Rep. Cindy Axne, as he worked his way across Iowa over the weekend. Mr. Biden has won the public backing of both of Iowa's Democratic congresswomen.

Ms. Warren's allies believe she will benefit from her sprawling organization of paid staff and volunteers on the ground in Iowa and other early voting states in addition to an aggressive paid advertising campaign. She is also expected to earn a wave of new endorsements from local progressive leaders on Monday as her allies work to spark a final-week surge.

The Warren-aligned Progressive Change Campaign Committee, the Working Families Party, and Black Womxn are set to announce more than 3,000 new endorsements for Ms. Warren including elected officials, economists, organization leaders, small business owners, and activists, according to said PCCC co-founder Adam Green. That is in addition to the endorsement of more than 40 Iowa Democratic officials and activists, the campaign announced on Sunday.

But sensing weakness, Ms. Warren's rivals are actively working to peel off her supporters.

Sen. Amy Klobuchar, one of the two other women in the race, sees Ms. Warren as one of her best targets as she fights to bump off one of the top four candidates. As Ms. Warren allies cheered her Des Moines Register endorsement, Ms. Klobuchar's team touted her endorsement from another one of the state's largest newspapers, the Quad City Times.

Iowa Democrat Deidre DeJear, who served as Kamala Harris' state chair before the California senator left the race, acknowledged Ms. Warren's uncertain status.

"I think there has been some stagnation," Ms. DeJear said of Ms. Warren's support. "I don't think that she's struggling by any stretch of the imagination, but I believe as it relates to people's temperature, poll numbers, folks have either made another decision or we're not necessarily seeing her support represented in the polls."

The rivalry between the Democratic Party's most liberal contenders, Ms. Warren and Mr. Sanders, looms largest as voters finalize their decisions. And in the fight for the left, a series of state and national polls over the weekend suggest Mr. Sanders is better-positioned than Ms. Warren on the eve of the first voting contest.

A New York Times/Siena College poll released Saturday showed Mr. Sanders with a slight – but not commanding – edge in Iowa, though polls also show that all four top candidates remain in the hunt there. In New Hampshire, several recent polls put Mr. Sanders out front, with Ms. Warren and the other top candidates lagging behind. And two polls released Sunday suggest that Ms. Warren is running well behind Mr. Biden and Mr. Sanders nationally.

Undecided Iowa voter Tyler Niska says he has narrowed his choices to Mr. Sanders or Ms. Warren, yet he fears that Ms. Warren would face the same political headwinds that plagued the party's last female nominee, Hillary Clinton, four years ago.

"Warren would probably do a better job, but Bernie has a much better chance of actually winning," Mr. Niska, a Des Moines resident, said as he waited in line outside a weekend Mr. Sanders rally in Ames.

"I'll probably go with Bernie," he said.

Mrs. Warren volunteer Amber Beitzel, of Bettendorf, said she is aware of recent polls showing Mr. Sanders with an advantage, and said it is something to watch. But she has seen Ms. Warren's operation up close and feels it is well positioned.

"There's a concern, obviously," said Ms. Beitzel, who works in nuclear medicine technology. "But I feel like working in her grassroots campaign, I see her organizers, I see the volunteers come. ... They're coming back with lots and lots of people who are interested in what she's saying. And it's very exciting."

This story was reported by The Associated Press. AP polling director Emily Swanson in Washington and AP writer Hunter Woodall in Manchester, New Hampshire contributed.