A large number of Coloradans announced their candidacy in the 2020 Democratic primary for U.S. Senate, seeking a shot at unseating U.S. Sen. Cory Gardner.

Gardner, a Yuma Republican, is seen as vulnerable after state voters handed decisive victories to Democrats in the 2018 midterm elections amid strong anti-Trump sentiment.

Here’s a look at who is running for the Democratic nomination for U.S. Senate, listed by the date they announced, in reverse chronological order.

Erik Underwood, former gubernatorial candidate

Underwood, a 40-year-old Denver Democrat who unsuccessfully ran for governor in 2018, announced Jan. 22 that he is running.

Underwood is a former Republican and was a staffer for former U.S. Sen. George Voinovich, R-Ohio. He says his time in Washington showed him how to get things done.

“I’m the only candidate who has ever worked in the United States Senate,” Underwood said of the large Democratic field. “John Hickenlooper has never worked in the United States Senate. Andrew Romanoff has never worked in the United States Senate. I have.”

David Goldfischer, University of Denver professor

Goldfischer, 68, filed paperwork with the Federal Election Commission to run for the seat Dec. 9. He teaches at the university’s Josef Korbel School of International Studies and founded the programs in international and homeland security. He has lived in Denver for the past 30 years.

Goldfischer believes the state and country could use an elected official who understands national security and the threat another country’s interference poses to democracy.

“At this moment, a clear voice understanding where we are in history is needed in this race,” he said.

John Hickenlooper, former governor and Denver mayor

Hickenlooper, 67, dropped out of the presidential race Aug. 15 and said he was considering a Senate run. A week later, he announced he is running for Senate.

“I’ve always said Washington was a lousy place for a guy like me who wants to get things done – but this is no time to walk away from the table,” the former governor of Colorado said in his announcement video. “… I’m not done fighting for the people of Colorado.”

In that video, filmed at the Denver brewpub he founded, Hickenlooper echoed his presidential pitch to voters, which focused on ending the conflict in Washington. And he promised to work on fighting climate change, prescription drug prices and economic inequity.

Michelle Ferrigno Warren, advocate and nonprofit leader

Warren, 48, filed paperwork Aug. 2 and formally launched her campaign Aug. 6.

She is an advocacy and strategic engagement director for the Christian Community Development Association. Warren and her husband founded Open Door Ministries.

“Politics has become a game of winning and losing,” she said in an interview. “When politics is just a game of winning and losing, we all lose. We can’t afford to lose anymore.”

Warren says she was born into privilege, as well as conservatism, but sought out a different life after college. She taught disadvantaged youth elsewhere in the country before moving back to Colorado and settling in southwest Denver. Her campaign’s mantra is “People over politics.”

Diana Bray, environmental activist

Bray, 58, is a psychologist and a self-described climate justice advocate who announced her candidacy April 2, 2019, with a focus on the environment.

“I’m running for US Senate to tackle our climate crisis head on by ensuring a just transition to renewable energy, and an economy that works for everyone,” she said in a kickoff message.

Stephany Rose Spaulding, professor and pastor

Spaulding, 40, is a professor of women’s and ethnic studies at the University of Colorado’s Colorado Springs campus and a Baptist pastor. She lost her challenge of Rep. Doug Lamborn, R-Colorado Springs, by 18 percentage points in November. She announced her Senate run April 1, 2019.

“I am not just for the people, I am of the people,” Spaulding said in a news release. “There are a number of candidates that feel for those who are under attack from this administration, but I am a candidate actually living the impact of dehumanizing policies and morally inept leadership.”

Andrew Romanoff, former Colorado House speaker

Romanoff, 52, announced Feb. 7, 2019. The former House speaker took a progressive stance on a variety of issues in his announcement, including Medicare for All, immigration reform and renewable energy. He also mentioned the Green New Deal to replace fossils fuels that’s being pushed by his former aide, U.S. Rep. Joe Neguse, D-Boulder.

Romanoff’s re-entry into politics comes after four years leading Mental Health Colorado, an influential advocacy group in the state. He previously lost a U.S. Senate Democratic primary to Michael Bennet, who now holds the seat, and unsuccessfully challenged then-U.S. Rep. Mike Coffman in the 6th Congressional District.

Trish Zornio, scientist

Zornio, 33, announced Jan. 19, 2019, the same day as the Womxn’s March. Before announcing, Zornio spent more than a year crisscrossing the state to visit with voters in all 64 counties.

In her announcement, she said: “I’m running because we need to think forward and solve the problems of tomorrow, not only the problems of yesterday, the way I have done my entire career. Thinking forward means being proactive to meet those challenges before they arise, which will be my commitment as your next senator.”

Lorena Garcia, nonprofit leader

Garcia, 36, was the first candidate to officially announce on Nov. 27, 2018, less than a month after the election. Garcia has spent her professional career working for different charities and is currently the executive director of the Colorado Statewide Parent Coalition.

“Throughout my career, I have had direct experience working in the field with people who are impacted by federal policies,” Garcia told The Denver Post. “I’ve sat with them while they cried when things didn’t pass or didn’t work out right. … I believe we can do much better as a country, starting with Colorado.”

Those who declined

Former Colorado House Speaker Crisanta Duran was floated as a possible Senate candidate but opted to run for the U.S. House instead against Rep. Diana DeGette, a fellow Denver Democrat.

Secretary of State Jena Griswold launched an exploratory committee in July 2019, raising $200,000 in two weeks as she considered a Senate campaign, but announced Aug. 9 that she would not run in 2020.

“After some heartfelt deliberation, I have decided that now is not the right time for me to run for the Senate,” she said then, citing her ongoing work as secretary of state. “I am moved by the encouragement I have received, and sincerely want to thank everyone for their support. I look forward to continuing to work to ensure that Coloradans have a democracy they can believe in.”

State Sen. Kerry Donovan, D-Vail, was also asked by some to run for Senate. But when Hickenlooper announced his candidacy, she endorsed him instead.

“It’s hard to explain what an honor it is when people ask you run for a higher office,” Donovan explained on Twitter. “I took those suggestions very seriously and gave it a lot of thought. I think Hickenlooper did too. He’s the right candidate to take on this challenge.”

Those who have dropped out

Angela Williams, state senator

Williams joined the race July 8. She represents northeast Denver in the Colorado Senate and emphasized her experience in the legislature during the campaign but failed to gain significant traction in a large primary led by John Hickenlooper and Andrew Romanoff. She dropped out Nov. 27 to run for re-election to the state Senate.

“Unfortunately, even now, as female candidates enjoy a historic level of support from voters, there are still elements of the Democratic Party seeking to promote male candidates at the expense of talented and smart progressive women,” Williams said in a news release.

“Fighting to give women, people of color and the underserved a voice isn’t always easy, especially when faced with strong headwinds from Washington, D.C.,” she added, a reference to the decision by Democrats in the nation’s capital to recruit and endorse Hickenlooper in the race against Republican Sen. Cory Gardner.

Alice Madden, former U.S. Energy Department official

Madden, who is also a former Colorado House majority leader, announced her candidacy May 9.

“I am, as of now, really the leading climate and clean energy champion in this race,” Madden said in an interview then. “And that’s why I got in this race, because I know there wasn’t anybody else, frankly, who could go to Washington and make things happen right away on this issue. It’s what I will lead on, it’s the first thing I’ll attack.”

But Madden called it quits Oct. 11, citing Hickenlooper’s entry.

“I had done an analysis that I had a path to victory if I could get progressive women and environmental groups to endorse, but after John got in, those avenues to victory seemed like they were closing,” she said in an interview.

Denise Burgess, Denver businesswoman

Burgess, who serves on the board of the Denver Metro Chamber of Commerce, announced her entry into the race Sept. 16.

Burgess is a second-generation Coloradan who worked with her father to grow the family’s heating and air conditioning business into a nationwide construction management firm, Burgess Services Inc. Her company has worked on the City and County of Denver Justice Center and the Westin Hotel at Denver International Airport.

Three days after joining the race, Burgess exited Sept. 19, citing a failure to gain traction.

Dan Baer, former U.S. diplomat

Baer, 42, is a Harvard and Oxford graduate who was U.S. ambassador to the Organization for Security and Cooperation in Europe between 2013 and 2017 and a deputy assistant secretary of state for four years before that. He served as Colorado’s executive director of higher education last year.

“Cory Gardner sits on the Foreign Relations Committee. I think one of the things I offer as a candidate going up against him is that I can go toe-to-toe with Cory Gardner on foreign policy issues,” Baer told the Denver Post on April 15, kicking off his campaign.

He exited the race Sept. 12, saying he would back Hickenlooper.

John Walsh, former U.S. attorney

Walsh, 57, was rumored to be entering the race for weeks before his April 16 announcement. For six years during the Obama administration, he was the top federal prosecutor in Colorado. He gained the immediate endorsement of former U.S. Attorney General Eric Holder, among others.

“This state has been so good to me and my family,” he said in a video announcement. “I spent my whole life fighting against institutions and individuals who have tried to get in the way of an open and fair system for all.”

But on Sept. 11, Walsh called it quits and threw his support behind John Hickenlooper. “I have concluded that Governor Hickenlooper offers our clear and best opportunity to defeat Cory Gardner,” he told supporters. “His long record of fighting for Coloradans is unmatched and leaves no doubt in my mind that he will win this campaign, and that he will make an outstanding Senator.”

Mike Johnston, former state senator

Johnston, 44, announced Jan. 31. The former teacher and school principal turned politician is best known for his work on education reform policies, including the state’s teacher evaluation law. This is also why he’s such a polarizing figure in the Democratic Party. During his gubernatorial run, the state’s largest teachers union took the unusual step of financing an attack ad against Johnston.

Johnston was an early fundraising front-runner after raising $1.8 million in the first three months of 2019. But he dropped out Sept. 3, after Hickenlooper joined the race.

“I think we had a very strong path to win this race before the governor got in and I think it was to give a positive vision of what we wanted to accomplish in the state and country,” Johnston said in an interview that day. “I think his entrance required this to be a very different kind of race and required a negative race that’s not one that matches my values and how I would want to lead.”

Ellen Burnes, Colorado State professor

Burnes, a 51-year-old finance professor at Colorado State University and former chair of the Boulder County Democratic Party, announced her candidacy April 17.

“It’s crystal clear that Washington is completely dysfunctional and our problems start with Cory Gardner’s failed leadership and his inability to represent our shared Coloradan values of hard work, progressivism and dedication to helping our fellow Coloradans have the resources they need to improve their lives,” she said in a press release.

On July 12, Burnes emailed supporters to say she was “withdrawing from the U.S. Senate race to pursue other community-focused leadership.”

Those who changed political parties

Christopher Milton, retired financial adviser

Milton, a 37-year-old from Alma, filed paperwork to run for Senate as a Democrat on Sept. 5, 2019.

“I am a moderate Democrat, socially liberal and fiscally conservative,” he said in an email at the time. “As a retired financial adviser, I strive to leverage my knowledge and experience for the benefit of all people, regardless of assets or any other discriminating classification.

But on Feb. 27, the Unity Party announced Milton had switched to their party.

“I’ve been as impressed with the Unity Party’s platform as I have been with their operations,” Milton said in a press release. “Term limits are one of the many things essential to healing our democracy, to reducing the influence of money.”