This race was the first test in a month that will go a long way toward demonstrating the power Donald Trump’s endorsement has in Republican politics. In two weeks, another Trump-endorsed celebrity candidate, television doctor Mehmet Oz, will stand before voters in a tight field for the Republican Senate primary in Pennsylvania. The following week in Georgia, a Trump Senate pick, former football star Herschel Walker, appears headed for victory, while his choice for governor, David Perdue, trails incumbent Republican Governor Brian Kemp by a sizable margin.