Trump endorsements face Republican runoff tests

Donald Trump's Republican endorsements face new tests Tuesday in primary runoffs in South Carolina and Oklahoma, where candidates backed by the US president are in close races.

In South Carolina, Trump-backed Senator Darline Graham faces congressman Ralph Norman in a runoff for the seat held for 23 years by her late brother Lindsey Graham. Graham was appointed to complete her brother's term after his death in July.

Graham led the first round two weeks ago with about 33 percent of the vote, while Norman had 25 percent, but she did not secure the majority needed to avoid a runoff. Trump travelled to South Carolina to campaign for her and held a telephone rally on the eve of the vote.

The Trump-supporting MAGA Inc. political organisation has spent more than $827,000 on voter calls and text messages in the race.

In Oklahoma, Trump's favoured candidate Mike Mazzei faces state attorney general Gentner Drummond for the Republican gubernatorial nomination. Drummond narrowly finished ahead of Mazzei in the first round in June, with both taking around a quarter of the vote.

More than $9 million has since been spent on the Oklahoma runoff, according to US media. Trump has criticised Drummond as a “fake Republican”, in part because Drummond opposed a proposed $4 billion aluminium smelter backed by the president. Drummond argued the project could damage local land and communities, while Mazzei publicly embraced it shortly before Trump endorsed him.

CNN reported that 10 Trump-endorsed candidates have been beaten in Republican contests this cycle, including six in August.