They also laid out a plan to reach out to voters via “hotdish” parties and office hours ahead of the fast-approaching Feb. 11 primary at a Tuesday press conference at the New Hampshire State House, while state lawmakers and staffers shuffled in and out of the capitol. The event achieved some measure of success — it drew a few TV news cameras and several New Hampshire campaign reporters. It was a smaller showing than if Klobuchar were there to campaign for herself, but it was better than no press at all.

While surrogate campaigners have long been an important part of presidential campaigns — Buckley recalled sending Boston Bruins legend Bobby Orr to northern New Hampshire when he worked on former Gov. Michael Dukakis' campaign in the 1980s to appeal to hockey fans — they’ve taken on new weight as senators are forced off the trail at the most inopportune time.

"We were all ready to do the usual things, knocking on doors and making phone calls and doing all of that. If we're called upon to do other things that we think will reach more people, I think all of us feel that we have to step up and do that." said Lucy Weber, Speaker Pro Tempore of the New Hampshire House of Representatives and a Klobuchar supporter. "All of us are making the effort to ensure that we get the message out because she can't be here."

A number of prominent out-of-state Warren supporters made their first trips to New Hampshire this week, among them Philadelphia Mayor Jim Kenney. On Friday, actor and activist Ashley Judd will hold meet and greet events in Dartmouth, Lebanon and Nashua.

Warren is also capitalizing on her home state’s proximity to New Hampshire to blanket the state with Massachusetts-based surrogates. The senator’s husband Bruce Mann will hold events all weekend. Rep. Jim McGovern will campaign on Saturday in Peterborough. On Sunday, Rep. Joe Kennedy III, Boston Marathon bombing survivors Jessica Kensky and Patrick Downes, who both lost legs during the 2013 tragedy, will hold events on her behalf across the state. The pair, who were depicted in the film “Patriots Day,” worked with Warren on a bill to help survivors of terror attacks receive medical care.

Not everyone is convinced the surrogate armies will make a difference.

"People in New Hampshire want to see the candidate and weigh the candidate themselves rather than the candidate's husband or wife or good friend. I think it's hard for a surrogate to transmit into a vote unless it's somebody of immense proportion that really attracts attention and can influence voters," said Neil Levesque, executive director of the New Hampshire Institute of Politics. "If you were to take sort of an Oprah Winfrey or Michelle Obama — rock stars in the country and the Democratic Party in particular, and have them come to New Hampshire, that's almost a game changer."

For Sanders, Levesque said, his well-known political brand and strong base of support should mitigate any concerns about his absence. But for Warren, whose support has slipped in recent New Hampshire polls, the next 19 days might be crucial.

"She's been lagging slightly, she needs to pick up her numbers. That's a more from behind situation, which is hard to do when you're stuck down in Washington," Levesque said.

Bennet, the Colorado lawmaker whose campaign is concentrating on New Hampshire but remains far behind the pack in state polls, pledged to do 50 town halls in the weeks leading up to the primary. He’s done 38 so far, his campaign says, and still intends to complete all 50 despite his Senate obligations.

In the meantime, his wife, Susan Daggett, and former Ohio Gov. Dick Celeste will stump for Bennet in New Hampshire this week, and Democratic strategist James Carville will head to the Granite State on his behalf soon as well. The campaign also plans to deploy five state lawmakers.

They’re up against the likes of former Vice President Joe Biden and former South Bend, Ind. Mayor Pete Buttigieg, who have been free to visit Iowa and New Hampshire while their rivals have been stuck in D.C. Biden’s campaign on Thursday announced a five-day tour across the state next week where he’ll be accompanied by former Governor John Lynch, and Biden is sending former Secretary of State John Kerry to New Hampshire on Sunday as well.

"You take a candidate who shows they work hard pounding pavement for votes, and combine that with the fact the others are down in Washington. That transmits an advantage for someone like Buttigieg," Levesque said, making a point that also applies to Biden. "He's a proven campaigner who is pounding the pavement and now his opponents can't even compete with him on that."

