Senator Kirsten Gillibrand used an appearance on The Late Show With Stephen Colbert to announce she was formally entering the race to become president in 2020 – the latest high profile Democrat to enter what will become a crowded field.

“I’m going to run for president of the United States, because as a young mom I’m going to fight for other people’s kids as hard as I would fight for my own,” she said, when asked if she had any news to share with the audience. “I’m filing an exploratory committee for president of the United States tonight.”

The formation of the exploratory committee will allow her to legally begin fundraising and organising her campaign, as she seeks to carve out a distinct presence in a field of candidates that could reach two dozen.

Texas Democrat Julian Castro, a former San Antonio mayor and top official in Barack Obama’s administration formally launched his White House bid on Saturday. Former congressman John Delaney has been running for more than a year, while senator Elizabeth Warren of Massachusetts formed an exploratory committee last month. Congresswoman Tulsi Gabbard of Hawaii said last Friday that she too, will run for president.

Who could be running against Trump in 2020? Show all 23 1 /23 Who could be running against Trump in 2020? Who could be running against Trump in 2020? Joe Biden The former vice president - poised to be a frontrunner - has announced his run. He recently faced scrutiny for inappropriate touching of women, but was thought to deal with the criticism well AFP/Getty Who could be running against Trump in 2020? Bernie Sanders The 2016 runner-up has announced that he will be running again in 2020 Getty Who could be running against Trump in 2020? Hillary Clinton The 2016 Democratic presidential candidate and former Secretary of State says she is “still considering” whether she will run again. Getty Who could be running against Trump in 2020? Pete Buttigieg The Indiana mayor and war veteran will be running for president. If elected, he would be the first openly LGBT+ president in American history. Getty Who could be running against Trump in 2020? Kamala Harris The former California attorney general will be running for president in 2020. Introduced to the national stage during Jeff Sessions’ testimony, she has endorsed Medicare-for-all and proposed a major tax-credit for the middle class. AP Who could be running against Trump in 2020? Elizabeth Warren The Massachusetts Senator has formally launched her bid for president in 2020. A progressive Democrat, she is a major supporter of regulating Wall Street. AP Who could be running against Trump in 2020? Beto O’Rourke The former Texas congressman told Oprah Winfrey that he “has been thinking about running for presidency”, but stopped short of formally announcing his bid to run in 2020. AFP/Getty Who could be running against Trump in 2020? Wayne Messam Mayor of the city of Miramar in the Miami metropolitan area, Wayne Messam has announced his bid. He intends to run on a progressive platform against the "broken" federal government. He favours gun regulations and was a signatory to a letter from some 400 mayors condemning President Trump's withdrawal from the Paris Climate Accord. Vice News Who could be running against Trump in 2020? Kirsten Gillibrand The New York Senator formally announced her presidential bid in January, saying that “healthcare should be a right, not a privilege.” Getty Who could be running against Trump in 2020? Cory Booker The New Jersey Senator has announced that he will be running for the presidency in 2020. If he secures the nomination he said finding a female vice president would be a priority. Getty Who could be running against Trump in 2020? John Delaney The Maryland congressman was the first to launch his bid for presidency, making the announcement in 2017. AP Who could be running against Trump in 2020? Julian Castro The former San Antonio mayor announced his candidacy in January and said that his running has a “special meaning” for the Latino community in the US. Getty Who could be running against Trump in 2020? Tulsi Gabbard The Hawaii congresswoman announced her candidacy in January, but is likely to face tough questions on her past comments on LGBT+ rights and her stance on Syrian President Bashar al-Assad. Getty Who could be running against Trump in 2020? Andrew Yang The entrepreneur has announced his presidential candidacy, and has pledged that he would introduce a universal basic income of $1,000 a month to every American over the age of 18. AFP/Getty Who could be running against Trump in 2020? Marianne Williamson The author and spiritual advisor has announced her intention to run for president. She had previously run for congress as an independent in 2014 but was unsuccessful. Getty Who could be running against Trump in 2020? John Kerry The former secretary of state has said he is still thinking about whether to run. Getty Who could be running against Trump in 2020? Michael Bloomberg The entrepreneur and former New York mayor– with a net worth of around $50bn – has said he will decide by the end of February whether to seek the presidency. AFP Who could be running against Trump in 2020? Howard Schultz Former Starbucks CEO Howard Schultz has not yet ruled out running for president in 2020, despite criticism that his bid could help re-elect Mr Trump by dividing the Democrat vote. AP Who could be running against Trump in 2020? Eric Holder The former attorney general has said he will decide in “the next month or so” whether to run as a 2020 presidential candidate. AP Who could be running against Trump in 2020? Eric Swalwell The California congressman said he is “ready to do this” and will decide before April whether to run. MSNBC Who could be running against Trump in 2020? Terry McAuliffe The former Virginia governor, who worked to elect Democratic governors during 2018 midterms, said there was a “50 per cent” chance he would run. AP Who could be running against Trump in 2020? Sherrod Brown The Ohio senator is still undecided about whether to run for president in 2020. Who could be running against Trump in 2020? Mitch Landrieu The former New Orleans mayor said he doesn’t think he will run for president, but “never say never”. AP Photo/Jacquelyn Martin

It is generally reckoned that candidates such as Ms Gillibrand, a senator for New York, who is well known but not among the top-rated potential candidates, benefit from declaring earlier in the cycle. This gives them more time to raise the vast sums required for a run, and to build awareness nationwide.

People such as Joe Biden and Bernie Sanders, should they decide run, already possess extensive networks that would allow them to raise money quickly. They also have greater national recognition. Figures such as congressman Beto O’Rourke, who narrowly failed to defeat Ted Cruz last year for a senate seat, have displayed they have the power to generate excitement among grassroots supporters that would also allow them to raise money quickly.

In her appearance broadcast on Tuesday evening, Ms Gillibrand, who was previously moderate but has shifted to the left on issues over the past decade, pitched herself as someone who would push for universal health care, public school and job training programmes, and seeking to tackle climate change.

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“You are never going to accomplish any of these things if you don’t take on the systems of power which make all of that impossible,” said Ms Gillibrand, who took the senate seat previously occupied by Hillary Clinton.

“Which means taking on institutional racism, it’s taking on the corruption and greed in Washington, and taking on the special interests that write legislation in the dead of night, and I know that I have the compassion, courage, and fearless determination to get that done.”

Reuters said that as senator, Ms Gillibrand has been outspoken about rape in the military and campus sexual assault several years before the #MeToo movement against sexual harassment and assault gathered pace in 2017.

In late 2017, as she pushed for a bill changing how Congress processes and settles sexual harassment allegations made by employees some prominent party leaders criticised her for being the first Democratic senator to urge the resignation of senator Al Franken, who was accused of groping and kissing women without their consent.