Sen. Klobuchar's lead surrogate so far has been her 24-year-old daughter Abigail Bessler, a New Yorker who works for the City Council by day and dabbles in stand-up comedy by night. In Iowa, her specialty is what the campaign calls "house parties" — gatherings in which several dozen curious Democrats chat over a potluck meal.

"I would never try to play my mom's part," Bessler told me. "I just talk about things she's done and what she will accomplish as president."

Sen. Sanders, by comparison has big guns, with the Oscar-winning filmmaker Michael Moore and the ultra-progressive New York Rep. Alexandria Ocasio-Cortez touring Iowa on his behalf. When the first week of the impeachment hearing ended early last Saturday, Sanders was able to join his two surrogates at a packed rally in Ames. But by the time the 78-year-old candidate ambled on stage, at the end of a long day that began on Capitol Hill, the crowd was in such a frenzy over speeches by Moore and Ocasio-Cortez, that he seemed upstaged by his understudies.

The Sanders crew is atypical. Most surrogates are welcomed politely, but their ability to change minds and win votes is limited at best. That has opened the door for other candidates in Iowa, where each poll seems to have a different front-runner.

Former Vice President Joe Biden and former South Bend, Indiana Mayor Pete Buttigieg have a free shot at Iowans. During the first week of the Senate trial, Biden held five public events in Iowa, while Buttigieg held eight. Businessman Andrew Yang, trailing but gaining in the polls, conducted a remarkable 23 live events in Iowa cities and towns.

Louise Esveld, a college administrator living in Pella, is typical of Iowans who have made a point of hearing the presidential candidates in person. "I found Yang to be very impressive," she said. "The impression you get is much different from what you see on TV. I came away with a lot more understanding of his views."

Yang is scurrying across the state trying to win over that very type of voter. Biden, on the other hand, has always favored a somewhat less hectic campaign schedule, but even he is stepping up his pace during the Senate trial. He finds himself in an unusual spot — trying to meet Iowans in person and ignoring impeachment, while nonstop television coverage of the trial contains constant references to him and his son, Hunter.

In week two, with the senators back in D.C., former Housing Sec. Julian Castro, himself a former candidate, stepped in for Warren. Also holding events was Warren's husband Bruce Mann, a Harvard law professor. He's articulate, although not one to rouse a crowd Michael Moore-style.

Castro and Mann were upstaged by another Warren surrogate who seems to attract enthusiastic crowds wherever he goes. He's Bailey, the senator's Golden Retriever. The other day at Drake University, Bailey held his own campaign event, hosted on campus by the school's bulldog mascot, Griff.

Every Iowa surrogate, it seems, has his day.

(c) Peter Funt. Distributed by Cagle syndicate.