In another big Virginia race, Republican Corey Stewart - once a state chairman to Trump's presidential campaign who was sacked for protesting the Republican National Committee - won the Republican primary to face Democratic Sen.
As results came in Tuesday, Sanford told a crowd in suburban Charleston: "I've always been a realist and at this point, based on the numbers I see, I'm going to lose this race".
With 98-percent of precincts reporting, Arrington led the race by about 2,500 votes - enough to avoid a runoff and secure the Republican nomination. Sanford's primary opponent, state legislator Katie Arrington, tried to frame the campaign about how critical Sanford has been of Trump. He is the "comeback kid" of SC politics, having survived his affair - part sordid, part comical - with an Argentine woman.
Arrington poured about $430,000 of her own money into challenging Sanford, arguing that he had become a creature of Washington, more eager to hear himself criticizing Trump on TV than to get things done in Congress.
Trump took aim at Sanford on Twitter just hours before the polls closed Tuesday in SC.
"He's MIA and nothing but trouble", Trump continued.
In his remarks Tuesday night, Sanford was unbowed, saying, "I stand by every one of those decisions to disagree with the president". Trump then told voters to support Arrington. "I look forward to working together with him to drain the swamp and continue making America great again".
South Carolina Rep. Katie Arrington, who is running for the first district of South Carolina, campaigns after voting in the primary election on June 12, 2018 at Bethany United Methodist Church in Summerville, South Carolina. She has served in the Statehouse since 2016.
‘There’s a special place in hell’ for Trudeau, White House adviser says
Over the weekend , Trump aides on Sunday morning news shows called Trudeau a backstabber who deserved a "special place in hell". Trudeau had said Canadians "are polite, we're reasonable, but also we will not be pushed around".
The toughest choice for Democrats was a close battle between Clark County Commission colleagues Steve Sisolak and Christina Giunchigliani - each hoping to be Nevada's first Democratic governor in two decades.
Democrats, meanwhile, could nominate state Rep. Jason Smith, a Joe Biden ally, to take on the Republican victor there.
Vangie Williams also won the Democratic primary in Virginia's 1st Congressional district.
Republicans in Virginia are picking between Corey Stewart, who has built his public profile on defending Confederate monuments, state delegate Nick Freitas, the favorite of the Koch brothers-backed Americans for Prosperity and a Rand Paul ally, and minister E.W. Jackson, who has taken a series of hardline conservative positions on social issues.
The most serious primary challenge to an incumbent member of Nevada's congressional delegation is conservative activist Sharron Angle's bid for Nevada's 2nd Congressional District. Heidi Heitkamp. The primaries are sleepy, but the two states will be among the nation's most competitive Senate battlegrounds in the fall. If he prevails, he's expected to advance to a general election against wealthy Democratic philanthropist Susie Lee.
There are three candidates, including Sanford, in the Republican primary.
"He's one of the most principled, consistent and conservative members of Congress I've ever known", tweeted Amash, one of the House's most outspoken conservatives.
McMaster, an early supporter of the president's 2016 campaign, had Trump's full endorsement, marked by a weekend tweet. In the swing state of Nevada, Democratic Representative Jacky Rosen sailed to the nomination to face vulnerable Republican Senator Dean Heller.