With the Senate's impeachment trial of President Donald Trump still underway, Sens. Klobuchar, Sanders and Warren are scrambling to make a big impact in the state in order to stand out in the 2020 presidential primary. WGBH Morning Edition host Joe Mathieu spoke with Iowa Public Radio reporter and co-host Clay Masters ahead of the Iowa Caucus next week. The transcript has been edited for clarity.

Joe Mathieu: So it's a mad dash from now to next Monday. I wonder how will candidates budget their time, including the four senators who cannot be there because of impeachment with so much ground to cover in Iowa. It's not like you can just go to Des Moines or Iowa City and call it a day.

Clay Masters: Yeah, and certainly we were seeing that over the last weekend. The three U.S. senators who are doing the big play here in Iowa — Bernie Sanders, Elizabeth Warren and Amy Klobuchar — were all spending as much time as they possibly could, holding events across the state.

I went to one of [Bernie Sanders'] events in Perry, Iowa — a small town in central Iowa — where he had Rep. Alexandria Ocasio-Cortez and filmmaker Michael Moore with him. They both talked. I saw off to the side that they had microphones at the ready to give to those in the audience to ask questions, but they cut the thing short because they had rallies in Fort Dodge, Sioux City and Storm Lake. Elizabeth Warren picked up the endorsement of The Des Moines Register editorial board, the state's largest newspaper, over the weekend. She certainly was here holding a lot of rallies as well. And Amy Klobuchar, the senator from Minnesota who has bet probably the most on Iowa, [has] gone to all of the state's 99 counties and spending pretty conservatively an amount of money on Iowa, but really hoping for this kind of last push. Being a neighboring senator from the Midwest, she has basically said, "Yeah, I wanted to do another 99-county tour before this. I'd rather be here. But I turn into a pumpkin at midnight and got to be back in Washington."

Mathieu: I wanted to ask you about that Des Moines Register endorsement. We see new polls out this week from The New York Times and Emerson College separately showing Bernie Sanders leading the pack in Iowa. But that at least used to be a pretty important stop. Does the Des Moines Register endorsement mean what it used to?

Masters: Yeah, it still does. Certainly readership of newspapers across the country [has] gone down. But there was this video that was surfacing that had Elizabeth Warren, when she was told by the staffer that she'd earned the endorsement of the Des Moines Register, she did kind of a little dance of excitement. And certainly all of these candidates are looking just for any kind of edge that they can bring, any kind of thing that they can boast about on the stage. Amy Klobuchar regularly likes to talk about how she won the endorsement of The New York Times and The Quad City Times, which is a newspaper that's on the eastern side of the state that borders Davenport and Rock Island — the two main cities of the four quad cities there. But certainly The Des Moines Register is still something that all the candidates are trying to get the endorsement of. They all meet with that editorial board.

Mathieu: Weather forecast is looking pretty forgiving, Clay. I've just looked at the forecast the next week. You're upper 30s, low 40s. Normally, candidates will be stepping over snow drifts in Iowa and New Hampshire. I'm assuming that's going to be pretty good for turnout.

Masters: That is going to be pretty good for turnout. And there are concerns about maybe some overcrowding in some of these precincts where there's been more voter registration since the last caucus. And so warmer weather, combined with just a lot of attention on this very open primary, could bring more and more people out. It also means good things for the week ahead [for] people that aren't tied up with the Senate impeachment trial. Of course, Andrew Yang, Pete Buttigieg [and] Joe Biden [are] all continuing to campaign very strongly throughout this week and taking advantage of this time that some of their competitors are stuck out in Washington.