UNITED STATES - SEPTEMBER 27: Sen. Cory Booker, D-N.J., and Sen. Kamala Harris, D-Calif., listen as Dr. Christine Blasey Ford testifies during the Senate Judiciary Committee hearing on the nomination of Brett M. Kavanaugh to be an associate justice of the Supreme Court of the United States, focusing on allegations of sexual assault by Kavanaugh against Christine Blasey Ford in the early 1980s. (Tom Williams/Pool Photo via AP)

The top tier of the prospective Democratic field in the 2020 presidential race is making its way to Iowa ahead of the first-in-the-nation caucuses that already are being described as more important than ever.

The caucuses, set to take place on Feb. 3, 2020, could give a much-needed early boost to more than one candidate in what is expected to be a crowded field that could include two dozen people.

“If you’re an underdog candidate, you’ve got to be in the top three to break out,” said Pat Rynard, who runs the political website Iowa Starting Line.

Sen. Cory Booker (D-N.J.) over the weekend visited the Hawkeye State for the first time since the 2016 campaign. He appeared at a string of events in subsequent days to campaign for 2018 midterm candidates.

“My chief of staff wouldn’t let me come up to Iowa because people would talk about presidential stuff,” Booker joked to a crowd in Boone on Monday. 

Sen. Kamala Harris (D-Calif.) is expected to make appearances for midterm candidates later this month over the course of several days. 

Sen. Bernie Sanders (I-Vt.), who narrowly lost the caucuses to Hillary Clinton in 2016, is set to visit Iowa later this month. It’s one of nine states he’ll visit while campaigning for Democratic candidates in the midterms.

A few others seen as top candidates if they choose to enter the race, including former Vice President Joe Biden and Sen. Elizabeth Warren (D-Mass.), have no current plans to go to Iowa.

And one underdog candidate, Rep. John Delaney (D-Md.), is practically living in Iowa. Delaney, the only Democrat to have officially entered the race, has already visited the state’s 99 counties and is running advertisements as part of a strategy of jump-starting his campaign with a strong finish in Iowa.

In 2016, Clinton and Sanders lapped a relatively small field, and the race for the Democratic nomination was clearly a two-candidate contest.

The next race is likely to be different, and big-name and underdog candidates alike will be looking for a major jump start from the Hawkeye State’s voters.

“Iowa will play its usual role at winnowing down the field,” predicted Jerry Crawford, a longtime Democratic Party operative in the state who served as an on-the-ground political fixer for Clinton. 

Another reason many Democrats think Iowa will have outsize importance in 2020 is that California’s primary will take place much earlier in the next presidential cycle.

While the Iowa caucuses and New Hampshire and South Carolina primaries will all take place first, California has moved its contest up to March.

Given advertising costs in the state, it will be important for candidates to emerge in Iowa to survive through California.

“You’re immediately going into the most important state to campaign in so unless you’re one of those candidates with a ton of independent money you’re not going to be able to create that media buzz,” said Rynard.