Bernie Sanders emerged as the frontrunner in the two earliest Democratic 2020 nomination voting states this weekend, Iowa and New Hampshire, according to the latest polls – but Elizabeth Warren received a powerful boost with an endorsement from the Des Moines Register newspaper in what is still considered an open race.

Warren had been slipping behind in Iowa, which holds the first vote in the nation with its caucuses just a week a way on 3 February, but the Register this weekend named her “the president this nation needs”.

.@ewarren’s competence, respect for others and status as the nation’s first female president would be a fitting response to the ignorance, sexism and xenophobia of the Trump Oval Office, the Register’s editorial board writes. #IAcaucus https://t.co/hLkImNiU2a — Des Moines Register (@DMRegister) January 26, 2020

Meanwhile, a surging Bernie Sanders, the original ultra-progressive in his runs for the White House in 2016 and 2020 elections, topped a new CNN and University of New Hampshire poll of likely Democratic primary voters in that state, released on Sunday, with 25% backing him – a considerable lead on former vice-president Joe Biden who was placed second with 16%. Pete Buttigieg, the former South Bend mayor, was third with 15% and Massachusetts senator Warren behind him with just 12%.

Sanders, who won the state by more than 20 points in the primaries four years ago, has gained four points since October and Warren has dropped six points in the same period. The state will vote in the Democratic primary on 11 February.

Meanwhile, a Washington Post-ABC News national poll, also published on Sunday, showed Biden and Sanders have emerged nationally as breakaway leaders in the competition for the Democratic presidential nomination.

It comes after a poll on Saturday also showed Vermont senator Sanders, 78, leading in Iowa, where Democrats will vote in the caucuses on 3 February. The New York Times/Siena College survey found him to be the first choice of 25% of voters – with Buttigieg in second with 18%, Biden at 17% and Warren at 15%.

For Warren it represents a marked change from September, when a poll showed her leading the field in Iowa with 22% of the vote, and she suddenly finds herself the underdog among the leaders in the field.

But despite this weekend’s disappointing results, it was Warren who won the highly coveted endorsement of Iowa paper The Des Moines Register.

In an editorial, published on Saturday, the paper said all of the remaining candidates “could make a fine president”, but singled out Warren as “the best leader for these times”.

It said she “is not the radical some perceive her to be. She was a registered Republican until 1996. She is a capitalist … But she wants fair markets, with rules and accountability. She wants a government that works for people, not one corrupted by cash.”

On the merits of her fellow candidates, the paper said Biden “would restore credibility in the White House and respect among allies around the world” and praised Buttigieg’s “refreshingly smart, youthful optimism”.

It noted Minnesota senator and 2020 rival Amy Klobuchar’s “track record of bipartisan achievement” and that Sanders “much like Warren … champions the working class”.

But, it said, Warren is the best candidate for the job: “Warren’s competence, respect for others and status as the nation’s first female president would be a fitting response to the ignorance, sexism and xenophobia of the Trump Oval Office…At this moment, when the very fabric of American life is at stake, Elizabeth Warren is the president this nation needs.”

In response to the endorsement, which is arguably more valuable, especially at this stage, than that of the New York Times, which she received earlier this month in tandem with Klobuchar, she thanked the Des Moines Register on Twitter on Sunday, adding: “Iowans are ready to make big, structural change – and I’m going to fight my heart out for everyone in Iowa and across the country.”

Thank you, @DMRegister, for your endorsement! Iowans are ready to make big, structural change—and I’m going to fight my heart out for everyone in Iowa and across the country. https://t.co/hsI14P5TpZ — Elizabeth Warren (@ewarren) January 26, 2020

Sanders’s campaign has surged in recent weeks – attracting the support of top progressives such as congresswoman Pramila Jayapal of Washington as well as key figure, New York congresswoman, Alexandria Ocasio-Cortez, who campaigned powerfully in Iowa on Friday – nominally for Sanders but in a performance that some saw more as, perhaps, an early 2024 promotion of her own potential run for the White House.

The latest developments in the crucial races come after a highly publicised spat between Warren and Sanders over comments made in a private meeting in 2018 that resulted in Warren accusing Sanders of calling her a “liar” in hot mic comments on national television.