The endorsement comes nine days before the Feb. 3 caucuses, providing enough time for Warren to highlight it in ads. In another highly anticipated marker next Saturday, the Register’s final poll will be published online and revealed live on CNN.

The Register is the most important media endorsement in the state. Its effect may be even more pronounced this year because polling indicates the race is still up for grabs and a significant portion of caucus-goers are open to supporting a candidate who isn’t their first choice.

Though Bernie Sanders and Joe Biden have each led in recent polls of the state, they are closely bunched with two other top-tier contenders, Warren and Pete Buttigieg.

The Massachusetts senator “is not the radical some perceive her to be,” the board said, noting that Warren was a registered Republican until 1996. The editorial casts her as a capitalist who supports fair markets “with rules and accountability” and advocates for a government that works for its people, not the influence of money.

The board drew contrasts between Warren and President Donald Trump on the economy, writing that Warren doesn’t measure economic success via the stock market or unemployment rate, as Trump does, but by how working families are doing. It also said her “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.”

Some of Warren’s policies seeking “big, structural change” on corporate governance or taxation go too far, the board cautioned. “But Warren is pushing in the right direction.”

And many of her proposals, it continued, "would improve life in America, and they are generally shared by the other Democratic candidates, who bring their own strengths to this race."

Two of the top four candidates — plus Minnesota Sen. Amy Klobuchar, who polls a distant fifth in Iowa — are stuck in Washington, D.C., six days a week until the conclusion of President Donald Trump’s impeachment trial in the Senate.

That reality has forced the senators to dispatch surrogates across the state throughout the week while Biden and Buttigieg continue to campaign there in person. Warren, Sanders and Klobuchar, however, traveled to Iowa on Saturday for events before they’re scheduled to return to Washington on Monday.

Warren was taking photos with supporters following an event in Muscatine when news of the endorsement landed.

“I just heard, and I’m delighted,” she told reporters in brief comments. “It really means a lot to me.”

In its editorial, the board praised the other top candidates as well. Biden “would restore credibility in the White House and respect among allies around the world.” Buttigieg “brings refreshingly smart, youthful optimism.” Klobuchar “offers a track record of bipartisan achievement,” and Sanders “champions the working class.”

“But at this moment, our country needs more,” the board said. “At this moment, when the very fabric of American life is at stake, Elizabeth Warren is the president this nation needs.”

In the latest Iowa poll, published Saturday morning by The New York Times/Siena College, Sanders led the pack with 25 percent support, followed by Buttigieg at 18 percent, Biden at 17 percent, Warren at 15 percent and Klobuchar at 8 percent. Nearly 40 percent of likely caucus-goers said they could be persuaded to support a candidate who isn’t their first choice.

The endorsement of Warren comes just one day after her campaign appeared to lower expectations in all of the early states. In a memo to supporters Friday, campaign manager Roger Lau framed the first four nominating states as “just the beginning.”

“We expect this to be a long nomination fight and have built our campaign to sustain well past Super Tuesday and stay resilient no matter what breathless media narratives come when voting begins,” he said.

In Iowa, candidates must garner 15 percent support in precincts to reach so-called viability, which makes them eligible to win delegates to the Democratic National Convention. Supporters of candidates who aren’t viable in the first round of voting can switch to another candidate in the second round.

Despite recent endorsements from The New York Times — which also backed Warren — and the Quad-City Times, Klobuchar appears to be in jeopardy of falling short of the 15 percent threshold in precincts. If that happens, Biden would be the biggest beneficiary, as a majority of Klobuchar’s supporters said they would back the former vice president if they had to choose among the top four candidates. Eighteen percent of them said they would support Warren in that scenario.

Biden is already bolstered by some of the state’s top Democrats: Tom Vilsack, the former governor and President Barack Obama’s agriculture secretary, and his wife have backed him, as have Reps. Cindy Axne and Abby Finkenauer, two of the state’s three congressional Democrats. The third, Rep. Dave Loebsack, supports Buttigieg.

Steven Shepard contributed to this report.