Editor's note: This page is no longer being updated; find the latest guide to the Democrats running for president and what likely Iowa caucusgoers think of them here.

© Copyright 2019, Des Moines Register and Tribune Co.

More than 20 candidates are running for the 2020 Democratic presidential nomination and the chance to take on President Donald Trump.

We're tracking who's running for the 2020 Democratic ticket and what Iowans think of them, including new results from each Des Moines Register/CNN/Mediacom Iowa Poll.

A poll of 401 likely Democratic caucusgoers in 2020 was conducted March 3-6, 2019, by Selzer & Co. The margin of error is plus or minus 4.9 percentage points.

► THE LATEST:A guide to Democrats running for president and what likely Iowa caucus participants think of them

The candidates are listed below in alphabetical order:

Joe Biden

The former vice president is chasing his third presidential run, making his first trip to Iowa at the end of April. He is a party favorite for his appeal to working-class Democrats — a segment of the voter base some feel was lost to Republicans in 2016.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 81%/15%/4%

December 2018: 82%/15%/4%

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 27%/46%

December 2018: 32%/50%

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Cory Booker

Booker, 49, a New Jersey senator and previous mayor of Newark, announced he was running for president Feb. 1. He's an outspoken progressive on many issues, including legalized marijuana, and criminal justice overhaul.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 53/14/33

December 2018: 49/12/39

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 3/6

December 2018: 4/11

Steve Bullock

The Montana governor has appeal for Democrats wanting to figure out how to win back red states. In 2016, he won re-election in a state that backed Trump. Bullock announced his candidacy in May and quickly started staffing up in Iowa.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 10/11/79

December 2018: 11/8/82

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 1/1

December 2018: 0/0

Julián Castro

Castro announced his presidential campaign in January and has visited Iowa several times, including the day before he formally announced. Castro, a former mayor of San Antonio, was former President Barack Obama's secretary of Housing and Urban Development.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 33/8/58

December 2018: 27/10/63

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 1/3

December 2018: 1/1

John Delaney

Delaney officially announced his run for president in 2017 and has visited all 99 counties in Iowa. The former Maryland representative in the U.S. House chose not to run for re-election in 2018 to pursue his presidential bid.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 27/12/61

December 2018: 25/11/64

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 1/1

December 2018: 1/1

Kirsten Gillibrand

New York’s junior U.S. senator is officially running for president as of March 17 after she launched her exploratory committee in January with an announcement on "Late Show with Stephen Colbert." Gillibrand has received acclaim in the party for her #MeToo activism.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 35/16/49

December 2018: 35/10/55

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 0/1

December 2018: 0/1

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Kamala Harris

The California senator announced her bid for president on Jan. 21 in a "Good Morning America" appearance. She has long been on the radar as a progressive woman of color. A former prosecutor, she gained attention for her role as a Judiciary Committee member asking pointed questions during Supreme Court Justice Brett Kavanaugh's confirmation hearings.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 58/9/33

December 2018: 49/10/41

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 7/18

December 2018: 5/11

John Hickenlooper

Hickenlooper made several trips to Iowa before officially joining the 2020 race on March 4. The former Colorado governor is seen as someone who may appeal to traditional Democrats and independents leaning away from Trump.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 24/10/65

December 2018: 24/9/67

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 0/1

December 2018: 1/2

Jay Inslee

Inslee is Washington’s governor and announced his presidential candidacy March 1, focusing on fighting climate change. He gained a national platform for opposing Trump’s policy banning travel from Muslim-majority countries and by welcoming Syrian refugees.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 17/8/75

December 2018: 11/8/82

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 1/1

December 2018: 0/1

Amy Klobuchar

The Minnesota senator is running for president on a campaign of Midwest values and has visited Iowa multiple times. Democrats say her centrist values and position as a female candidate make her a viable option.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 43/15/41

December 2018: 38/8/54

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 3/6

December 2018: 3/5

Beto O’Rourke

The former U.S. House member announced his 2020 run March 14 following a close but ultimately unsuccessful run to unseat U.S. Sen. Ted Cruz in the 2018 election. But the 46-year-old Texan retained a following nationwide and came to Iowa the day of his announcement for a three-day campaigning stint across the state.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 52/12/36

December 2018: 53/11/36

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 5/11

December 2018: 11/23

Bernie Sanders

Sanders is the Vermont senator who challenged Hillary Clinton in the 2016 Democratic caucuses and primaries. He narrowly lost Iowa that year. Sanders announced his 2020 campaign on Feb. 19.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 71/25/4

December 2018: 74/22/4

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 25/38

December 2018: 19/33

Eric Swalwell

The U.S. representative from California launched his 2020 bid in April, but had been a frequent visitor to Iowa before then. Swalwell, an Iowa native, has said he thinks there’s a call for younger voices in the nomination race, and as a 38-year-old, he could fit the bill.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 19/10/71

December 2018: 20/10/70

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 0/0

December 2018: 0/1

Elizabeth Warren

Warren has been on Democrats’ presidential radar for years and announced her 2020 bid in late 2018. In Iowa, she has attracted big crowds during her visits and won admirers for the personal touch she adds when she talks about liberal issues.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 63/20/17

December 2018: 64/20/16

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 9/21

December 2018: 8/18

Andrew Yang

Yang announced his bid for the presidency in late 2017. The coastal entrepreneur has advocated for "Medicare for All" and for a universal basic income of $1,000 each month for all Americans age 18-64.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 7/12/81

December 2018: 5/12/83

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 0/0

December 2018: 0/1

► More: Track all the candidates' visits to Iowa

New to the Iowa Poll in March

Michael Bennet

Bennet, Colorado’s senior U.S. senator, was recently diagnosed with cancer after rumors of a presidential run. He said he would officially declare his run once he was cancer-free. He was not included in the December 2018 poll.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 18/7/75

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 1/2

Pete Buttigieg

Buttigieg announced his presidential exploratory committee Jan. 23 and presidential candidacy on April 14. Buttigieg, the mayor of South Bend, Indiana, has stopped in Iowa several times, saying he thinks his age and experience are assets in his potential bid.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 17/10/73

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 1/2

Bill de Blasio

The mayor of New York City officially announced his presidential candidacy May 15. He quickly visited Iowa twice, for .

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 21/29/51

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 0/0

Tulsi Gabbard

Gabbard announced she's running for president in January. She’s one of Hawaii’s representatives in the U.S. House and the first Samoan-American and Hindu member of Congress. She has made two trips to Iowa so far, talking about foreign policy.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 22/15/64

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 0/2

Marianne Williamson

Williamson announced her presidential bid the last week of January, shifting from writing about spirituality and miracles to politics and visited Iowa the same week. She has criticized corporate influence in American government and wealth disparity in addition to continuing to speak on spiritual topics, putting her in a unique position in the large 2020 field.

Iowa Poll results, Favorable/Unfavorable/Not Sure

March 2019: 8/11/80

Iowa Poll results, First Choice/Combined first and second choice

March 2019: 0/0

Not yet polled

Wayne Messam

The mayor of Miramar, near Miami, announced his presidential candidacy in late March. He is little-known nationally, but told Iowans in his first visit that mayors are better suited to being president than senators or congressmen.

Seth Moulton

The Massachusetts representative officially joined the presidential race in April. The Democrat is best known for his opposition to U.S. House Speaker Nancy Pelosi becoming speaker again. He visited a high school in Iowa on his first caucus trip.

Mike Gravel

This former Alaska U.S. Senator entered the race this year, joining on a platform of pushing the Democratic party further left. He officially joined the face April 2, and previously ran for president in both the Democratic and Libertarian party nominations in the 2008 election cycle.