Trump speaks during a campaign rally at Drake University in Des Moines, Jan. 30. Photo: Saul Loeb/AFP via Getty Images

The star guest spotted at a Sheraton in Des Moines in recent days was Elizabeth Warren's golden retriever, Bailey. But in a conference room off the same hotel lobby, Trump campaign operatives have been quietly orchestrating a massive operation for tomorrow's Republican caucuses.

Why it matters: The Trump campaign is using Iowa as a testing ground for the rest of the campaign trail.

  • It's testing its field program, bandwidth of staff and volunteers on the ground, and the efficiency of its surrogates. Trump rallied in Iowa himself last week, and roughly 80 members of Congress, Cabinet secretaries and administration officials are coming tomorrow.
  • The campaign said it recruited 2,400 volunteers for caucus efforts alone, holding 93 training sessions and making 125,000 phone calls.
  • “The caucus is a test of turnout [of volunteers, and staff],” Stephanie Alexander, regional political director for the Trump campaign, tells Axios. “This is a really, really good way for us to see how far we can get and how far our reach is with the staff that we have on the ground and the volunteers that have already committed.”

Surrogates: Top surrogates per the Trump campaign: Lara Trump, Donald Trump Jr., Eric Trump, Kimberly Guilfoyle and Brad Parscale.

  • They’ll run through Trump’s greatest hits throughout different parts of Iowa, particularly the passage of the USMCA and signing phase one of the U.S.-China trade deal, playing straight to the Iowa farmers.

Between the lines: Iowa has a lot of unaffiliated voters, and the Trump campaign plans to focus heavily on voter registration, including converting independent and Democratic voters supportive of POTUS to register as Republicans.

  • It’s also the first opportunity since 2016 for Iowans to affirm their support for Trump.
  • It's also an important state for Republicans to take seriously, given GOP Senator Joni Ernst is up for re-election and the GOP is eyeing two House seats they lost in 2018.

Go deeper: Biden surrogates test electability argument ahead of Iowa clash with Sanders

Go deeper

Republicans and Dems react to Coney Barrett's Supreme Court confirmation

President Trump stands with Judge Amy Coney Barrett after she took the constitutional oath to serve as a Supreme Court justice during a White House ceremony Monday night .Photo: Tasos Katopodis/Getty Images)

President Trump said Judge Amy Coney Barrett's Senate confirmation to the Supreme Court and her subsequent taking of the constitutional oath Monday was a "momentous day," as she she vowed to serve "without any fear or favour."

  • But as Republicans applauded the third conservative justice in four years, many Democrats including Speaker Nancy Pelosi (Calif.) warned of consequences to the rush to replace the late Justice Ruth Bader Ginsburg ahead of the Nov. 3 election, with progressives leading calls to expand the court.
Ina Fried, author of Login
23 mins ago - Science

CRISPR pioneer: "Science is on the ballot" in 2020

Photo: "Axios on HBO"

In her three decades in science, Jennifer Doudna said she has seen a gradual erosion of trust in the profession, but the recent Nobel Prize winner told "Axios on HBO" that the institution itself has been under assault from the current administration.

  • "I think science is on the ballot," Doudna said in the interview.

Why it matters: That has manifested itself in everything from how the federal government approaches climate change to the pandemic.

Ted Cruz doesn't think the Hunter Biden attacks are working

Republican Sen. Ted Cruz told "Axios on HBO" he doesn't think the Trump campaign's focus on the Biden family's business dealings are having any sway with voters.

The big picture: After watching the Trump-Biden debate with "Axios on HBO" on Thursday night, Cruz said he thought Trump had done very well. But when asked whether he thought voters were moved by the release of the Hunter Biden emails, Cruz replied, "I don't think it moves a single voter."