India, Aug. 26 -- US Senator Darline Graham has won the Republican primary runoff to keep the South Carolina seat once held by her late brother, Lindsey Graham, defeating Congressman Ralph Norman on Tuesday after US President Donald Trump threw his full political weight behind her candidacy in the race's closing days.

Graham, 62, was appointed to the seat by Governor Henry McMaster after her brother died suddenly in early July from a heart condition at the age of 71, only weeks after he had won his own primary for a further term. She had never previously held or sought elected office before her appointment, though she had led a South Carolina state agency of around 130 employees that supports blind residents.

With roughly 71 per cent of...