Elizabeth Warren and Cory Booker are considering tele-town halls so they can beam into early-voting state campaign events. Advisers to Bernie Sanders hope his star supporter, Rep. Alexandria Ocasio-Cortez (D-N.Y.), will stand in for him in Iowa. And Amy Klobuchar is preparing to scramble onto late-night flights while sending a small army of supporters to campaign in her stead.

The likely Senate impeachment trial of President Trump, expected to dominate the first half of January, is scrambling plans for the sizable number of Democratic presidential candidates who, as senators, will be required to sit as jurors — taking them away from the final sprint of campaigning before voting begins Feb. 3 in Iowa.

The convergence of impeachment proceedings and presidential politics is without precedent, with five of the 15 contenders for the Democratic nomination looking for creative ways to remain in the mix in early-voting states while spending most of their time back in Washington.

For the five senators, the impeachment trial poses an asymmetric threat. While they are in Washington six days a week as jurors in what could be a multiweek impeachment trial, the 10 remaining candidates will be free to swarm across Iowa, New Hampshire and other states. Former vice president Joe Biden could also be swept up in the impeachment swirl, forced to defend himself and his son Hunter from escalating attacks from Republicans.

No state looms larger than Iowa, where the Feb. 3 caucuses have tended to reward candidates who forge a personal bond with voters. Some Democrats say the absence of the senators — including Warren (D-Mass.) and Sanders (I-Vt.), who polls show are at or near the top of the pack — could present an opening for Biden and Pete Buttigieg, the mayor of South Bend, Ind. Both also rank toward the top of polls there, and neither will have competing job responsibilities in January. (Buttigieg’s tenure as mayor ends in January.)

“I don’t think it’s like a death sentence for many of the senators, but it’s certainly an opportunity for Biden and Buttigieg to make up some of the ground game and put some points on the board,” said Sean Bagniewski, chairman of the Polk County Democrats.

Already, the entire field is urgently stockpiling endorsements, sharpening attacks and pouring money into television ads in recognition of the fact that the next several weeks — a time frame already split by the holidays — could be their final chance to leave a lasting impression with voters before an all-consuming trial begins early next year.

“I can barely imagine how nerve-racking and stressful it is,” Sen. Richard Blumenthal (D-Conn.) said of the plight of his Senate colleagues. “The organizers of events are all going to say, ‘If you fail to be at this event, you’ve lost.’ They’re all jealous lovers.”

The stark logistical and political challenges factored into the recent exit from the contest of Sen. Kamala D. Harris (D-Calif.) have caused anxiety among the remaining campaign strategists and candidates. As Sanders bluntly put it last month: “It will make my life and other senators’ lives more difficult.”

The impeachment proceedings also underscore a unique challenge Democratic candidates have struggled against this year: They have frequently found themselves eclipsed both by Trump’s explosive controversies and congressional Democrats’ response, making it difficult for most to attract enough notice to break out from the pack. A top strategist on a Democratic campaign privately vented frustration about this trend Thursday.

Now the candidates have a different hurdle to clear — how to ensure a continued presence in the early states that have historically played an outsize role in determining who wins the nomination.

If the Senate is presented with articles of impeachment, according to the chamber’s rules, senators would consider them every day but Sunday starting at 1 p.m., unless otherwise ordered. Republican and Democratic aides and senators cautioned this week that all of the particulars — including trial length and witnesses — are up in the air.

The Democratic senators running for president have promised to be there. Senate Minority Leader Charles E. Schumer (D-N.Y.) gave a presentation to Democratic senators on Wednesday about the mechanics of an impeachment trial, according to two people familiar with meeting who spoke on the condition of anonymity to describe a private discussion. According to one of the people, members were shown video clips from President Bill Clinton’s 1999 impeachment trial, which lasted five weeks.

A trial is expected to begin in early January — about the time candidates would normally begin camping out in the states where they think they have the best early shot. For Klobuchar (D-Minn.), who received positive reviews in the last debate and is getting a closer look from some voters, Iowa is crucial.

Klobuchar said she would rely on supporters such as her husband, her daughter and Minnesota Gov. Tim Walz to help campaign for her in January, noting that Walz used to represent a congressional district on the border with Iowa. She is also considering video appearances.

“I’m going to deploy them, and I’m going to go myself when I can,” Klobuchar said in an interview. “I’m sure there will be some late-night planes.”

Iowa is also seen as a crucial battleground for Warren, who has an aggressive field operation in the state. “We are looking at all options,” said Warren communications director Kristen Orthman, who raised the possibility of travel by Warren’s husband, Bruce Mann, and remote appearances by Warren. Mann normally keeps a lower public profile than the spouses of other top contenders.

Sanders also has focused intensely on Iowa, where he has been running TV ads in recent weeks and plans to spend the next several days. He campaigned with Ocasio-Cortez there last month, drawing large and enthusiastic crowds.

Rep. Ro Khanna (D-Calif.), a co-chair of the Sanders campaign, said Ocasio-Cortez could “absolutely” help fill in or amplify his message during a trial. “It’s going to be an advantage for him in the sense that he has a strong grass-roots organization that is fueled organically and [is] least dependent on the personality of the candidate,” Khanna said in an interview.

A representative for Ocasio-Cortez did not comment when asked about her plans. A Sanders campaign spokesman declined to discuss the campaign’s plans during an impeachment trial.

Booker (D-N.J.) spent Thursday in Iowa, where he delivered a speech urging voters to help keep his campaign going and reminding Iowans that they propelled another African American candidate: Barack Obama.

“I’m here to ask for your support. Let me be more blunt. I’m asking you when your caller ID is showing that some pollster’s calling you, pick up the phone and answer,” said Booker, who needs strong results in public surveys to qualify for this month’s debate.

Booker is considering tele-town halls as an option for January and intends to be in Iowa as much as possible, according to a person familiar with his plans. Like others interviewed for this story, the person spoke on the condition of anonymity to describe private discussions.

The fifth senator in the race, Michael F. Bennet (D-Colo.), is increasingly focused less on Iowa than New Hampshire, about half the distance and flying time from Washington. The shorter commute means Bennet could arrange weeknight events during the trial without missing any of the proceedings.

For Biden, the impeachment trial presents a different kind of challenge. Some Republicans are looking to draw attention to Joe and Hunter Biden, as they seek to defend Trump’s decision to press Ukrainian President Volodymyr Zelensky to “look into” the two. Senate Republicans have privately debated whether they should use the trial to scrutinize the Bidens, who have not been accused by any authorities of wrongdoing.

Asked Wednesday whether Republicans should press for them to testify, Senate Majority Whip John Thune (R-S.D.) said, “I don’t know if decisions have been made about that.”

He added, “If I’m Joe Biden, I think I’m going to be anxious to have this get behind us pretty quickly.”

Biden got into a startling exchange Thursday with an Iowa farmer who challenged him on Hunter Biden’s activities in Ukraine, prompting Biden to call the man “a damn liar.”

Some Democrats have expressed worry about the added burden of Biden having to defend himself, even though the Republican allegations are unsubstantiated. Biden’s supporters said they expect his campaign to continue to mount a vigorous defense. “I don’t think the Biden campaign is the least bit worried about something that has no merit to it,” said Sen. Doug Jones (D-Ala.), a Biden supporter.

Another variable that all the candidates may have to confront is whether an impeachment trial changes the way voters think about the candidates and the primary. Although impeachment has dominated Congress’s focus, it has generated less interest so far on the campaign trail, where candidates don’t dwell on it and voters rarely pose questions on the topic.

“People are asking about trade. People are asking about health care. It’s just not on people’s mind,” said Alan Feirer, chairman of the Madison County Democrats in Iowa. “I don’t know how much of a difference it’s going to make.”

Annie Linskey and Michael Scherer contributed to this report.