Twenty-three candidates are vying to become the Democratic nominee to face President Trump ahead of next year's US Presidential election.
A front runner has already emerged, with former Vice President Joe Biden leading in the polls.
"We need a President willing to lead, who will insist on dramatic change," Mr Biden told supporters at his official launch. "The single most important thing we have to accomplish to get this done is defeat Donald Trump."
"America is coming back in a way that relates to all our principles, decency, we're going to lead again by example," was his message to the world.
With more than 18 months before the 2020 election, Mr Biden is already surging ahead in polls, sitting at 39.1 per cent, followed by Bernie Sanders sitting on 16.4 per cent as preferred Democratic Presidential nomination according to RealClear Politics.
Elizabeth Warren and Kamala Harris were polling third and fourth respectively.
However, Mr Biden's pre-campaign saw allegations he made people uncomfortable, with allegations of touching that included kissing a woman's head and rubbing noses with another. He released a statement saying he would be "more mindful about respecting personal space in the future".
The Democrats' desire for generational change within the party would also be an issue for Mr Biden, who would be 78 if he were to win the election.
It was a problem not extended to his closest rival Mr Sanders, aged a year older, who took out the youth vote in the 2016 Democratic race against Hillary Clinton.
There is also 37-year-old in the race, Pete Buttiegieg.
"Some people think all there is about us is eating avocado toast... but we're the generation with the most at stake ... I think we've earned a place in the national conversation," he said.
The party also wanted a woman as President, however the support has only generated a 8.4 per cent preference for Elizabeth Warren.
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