MUSCATINE, Iowa — Three senators sitting on the "jury" of President Donald Trump's impeachment trial who are also running for president returned to Iowa this weekend, just over a week until the state's first-in-the-nation caucuses.

Sens. Bernie Sanders, Elizabeth Warren and Amy Klobuchar made a beeline for the Hawkeye state once they were cleared from Capitol Hill on Saturday after Trump's defense lawyers wrapped up their arguments for the day. A fourth senator also in the race, Michael Bennet, made his way to New Hampshire.

Warren breezed into her first event of the weekend here, greeting the room of about 100 with a somewhat out-of-breath, "Hello, Muscatine!" She took several rounds of questions from voters, though none were about the impeachment proceedings. The senator did not mention impeachment or being in Washington last week.

Warren was welcomed back to the state with the endorsement from The Des Moines Register editorial board. She hasn't led in an Iowa-specific poll since September, but the Register’s endorsement has a record of spurring support in past elections; 538's Nate Silver found that a nod from the Register is worth a poll boost of 3 percentage points.

A New York Times poll of Iowa on Saturday found Sanders in the lead with 25 percent, followed by Pete Buttigieg at 18 percent, Joe Biden at 17 percent and Warren in fourth place with 15 percent.

Asked by NBC News after a campaign event in Muscatine about the endorsement, Warren said: "I just heard and I am delighted. It really means a lot to me. I'm very happy."

In a pivot from her usual rhetoric, Warren made her closing pitch ahead of the Feb. 3 vote, asking caucusgoers to commit her because she's a fighter.

Sen. Elizabeth Warren, D-Mass., is told by an aide that she received the endorsement of the Des Moines Register newspaper in Muscatine, Iowa, on Jan. 25, 2020. Brian Snyder / Reuters

"We have to decide whether to give into the fear, or whether to fight back. Me? I'm fighting back," she said to applause in Muscatine.

"This is a hard time for our country," Warren continued "But I'm here today with you because I am filled with optimism. And the reason for optimism is because I believe. I believe in you. I believe in us. I believe in the America we can build together."

While in Washington, she has stayed connected to Iowa through campaign ads and several local news interviews.

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Three hours after Sanders walked off the Senate floor in Washington, he touched down Saturday in Ames, with enough time to add an appearance at a previously scheduled surrogate event to his 36-hour whirlwind barnstorming across Iowa before he needs to return to D.C. for the resumption of the impeachment trial on Monday.

At his rally in Ames, Sanders talked through how the trial had affected the campaign's plans.

"Our schedule, needless to say, has been significantly changed," Sanders said, adding that that made the campaign dependent on surrogates like filmmaker Michael Moore and Rep. Alexandria Ocasio-Cortez, D-N.Y., "to kind of carry the ball forward for us."

Sanders made it clear on Capitol Hill last week where he would rather be. "Between you and me, I would prefer to be in Iowa," he said.

Klobuchar chartered a plane from D.C to Cedar Rapids, arriving at a house party in Hiawatha to tell the crowd of about 120 people, "We have been very busy! I have to switch gears, as you can imagine, from being a juror" to being a presidential candidate on the trail again. At multiple events on Saturday, Klobuchar urged those in the room to work hard for her.

"It's like I turn into a pumpkin on Monday morning, on that 6 a.m. flight back from Des Moines," Klobuchar told a crowd of more than 100 in a sports bar in eastern Iowa. "I need you to talk about me to other people."

Leading up to the impeachment trial, there was concern from supporters that the senators’ inability to campaign in Iowa could put them at a competitive disadvantage to rivals Joe Biden and Pete Buttigieg, who, along with Andrew Yang, plan to be in the state every day leading up to the caucuses.

The senator-candidates have gotten creative in pulling out all the stops for surrogates spread across the state, and caucusgoers told NBC News they enjoy hearing from surrogates because it gives them a sense of the candidates' personalities behind the scenes.

"We only see how candidates act in front of a crowd when the world's watching, but I want to know what they're like just in a room with no cameras, just how they are as a person," said Matthew Kolb told NBC in Lamoni, after he took a photo with former presidential candidate and now-Warren surrogate, Julian Castro.

Castro stumped for Warren in snowy southern Iowa, speaking to students in a peaceful chapel on Graceland University's campus, asking them to put in extra work.

"You really are her voice as an ambassador on the ground in Iowa, in this campaign," Castro told the group. "And so I just want to ask you to please redouble your efforts and put every single ounce of energy and enthusiasm and effort you can to ensure that Elizabeth Warren wins here in Iowa."

As the Sanders campaign focuses on building a progressive coalition, Sanders' surrogates are leaning in to his message of "not me, us."

Ocasio-Cortez stumped for Sanders on Friday night in Iowa City, but, surprisingly, didn't mention the candidate's name. Instead, Ocasio-Cortez focused on the policy proposals that are hallmarks of the progressive movement, like the Green New Deal, "Medicare For All" and criminal justice reform.

Rep. Alexandria Ocasio-Cortez, D-N.Y., speaks as a surrogate for Democratic presidential candidate Bernie Sanders on Jan.24, 2020, in Iowa City. Sue Ogrocki / AP

Ocasio-Cortez's star power seemed to work as more than 800 people came out to a rally even Sanders thought he couldn't attend.

In addition to holding a tele-town hall for about 12,000 Iowans, Klobuchar employed her family on the trail this week. Her daughter, Abigail Bessler, took time off work in New York to host "hot dish" house parties with her dad — not your typical family vacation.

"I mean our family has never been typical, but I think that's what makes us great," Bessler said after delivering her mother's "Taconite Tater Tot" to a supporter's home in West Des Moines.

"I think having me out there — I think people do value it," Bessler added. "There are a lot of undecided people who are starting to tune in and hear from neighbors and friends that are already supporting our campaign about why she's the best person to beat Donald Trump."

"It all helps, everything helps," Sue Amosson of West Des Moines said of seeing Klobuchar's surrogate instead of the candidate herself.

Davis, who is currently choosing between supporting Klobuchar and Warren, added, "I love how down to earth Amy is — her daughter Abigail is clearly down to earth, too — but I do wonder if that will appeal all around the country."

Ronald Whitehorn from Wapello, who is backing Yang, with Klobuchar as his second choice, doesn't think the impeachment trial will hurt the senators who can't be in Iowa next week because volunteers on the ground can carry the campaign.

"We know they have a responsibility, a day job to do," Whitehorn said.