Voters today will deliver a verdict on two key tests on the power of President Donald Trump’s endorsement within the Republican Party. The highest-profile race is in South Carolina, where Sen. Darline Graham is aiming to also replace her late brother on the November ballot. Follow live updates.

The primary runoff in South Carolina between Sen. Darline Graham and Rep. Ralph Norman is another test of President Trump's influence. He's backing Darline, sister of the late…

The Trump-endorsed senator and political neophyte is in an unpredictable Aug. 25 Republican special primary runoff election against Rep. Ralph Norman.