Kamala Harris
The California senator struggled to gain traction in recent months.
Former VP becomes 20th Democratic candidate to join the race to take on Donald Trump.
Former Texas congressman Beto O'Rourke has announced he is running for president in the 2020 elections. He joins 14 others who will be vying for the Democratic nomination, including senators Bernie Sanders, Elizabeth Warren, Kamala Harris.
Harris kicked off her campaign to become the next party presidential candidate, but there are a number of challenges she'll face