Annie Andrews, a former paediatrician and political newcomer, won South Carolina's US Senate seat, making her the first Democratic senator from the state in 28 years, according to CBS projections cited by the BBC.
Andrews defeated Republican Darline Graham, who was appointed to the seat in July after the death of her brother, Senator Lindsey Graham. Graham had received support from President Donald Trump for the appointment.
During her primary campaign, Graham acknowledged limited expertise in national security and foreign policy. When asked about US policy towards Taiwan during a debate, she said: "National security is not my thing, not my area of expertise, but I do support the military."
Lindsey Graham, first elected to the Senate in 2002, was known as one of Washington's most influential voices on foreign policy and an advocate for US military intervention overseas.
Trump won South Carolina by 18 points in 2024.