Donald Trump has a strong voter base but will need to convince women, among others, to vote for him.
One of Joe Biden's challenges is to attract the more progressive left-wing voices.
But both are faced with the same difficult task: to get people to use their voice.
- Since so few relatively actually vote, it can be decided on a few percent in the groups you target, says Frida Stranne, political scientist and US expert.
In the video, we go through which voters the presidential candidates must succeed in convincing.