Trump urges Republicans to oust Rep. Mark Sanford in primary

In a stunning upset, first-term state lawmaker Katie Arrington unseated incumbent Rep. Mark Sanford, following President Trump's eleventh hour tweet. (Video: Joyce Koh/The Washington Post)

President Trump has urged South Carolina’s Republicans to oust Rep. Mark Sanford (R-S.C.) in Tuesday’s primary — the first time the president has endorsed an opponent over an incumbent of his adopted party.

“Mark Sanford has been very unhelpful to me in my campaign to MAGA,” Trump tweeted. “He is MIA and nothing but trouble. He is better off in Argentina. I fully endorse Katie Arrington for Congress in SC, a state I love. She is tough on crime and will continue our fight to lower taxes. VOTE Katie!”

Trump sent the tweet just three hours before polls closed in South Carolina’s 1st District, but loyalty to the president had become a defining issue of the campaign. Arrington, a state legislator backed by a number of the state’s Republican leaders, had attacked Sanford for criticizing the president and voting against a funding bill that would have shifted some money to the construction of a border wall with Mexico. One of Arrington’s strategists, Michael Biundo, had been an adviser to Trump’s 2016 campaign.

“Thank you, Mr. President!” Arrington tweeted on Tuesday afternoon. “Together we will continue to Make America Great Again!” Within minutes, her campaign had also paid for a robocall, informing Republican voters of the tweet.

The reference to “Argentina” in Trump’s tweet invoked the scandal that briefly forced Sanford from the national stage. In June 2009, as governor of South Carolina, Sanford admitted that he was having an affair with an Argentinian journalist, and had briefly left the state to visit her in Buenos Aires. Sanford’s marriage ended soon thereafter, but he finished his term and, in June 2013, won his House seat in a special election. Trump’s jab did not sit well with some Republicans.

“Mark Sanford’s job is to support and defend the Constitution,” wrote Rep. Justin Amash (R-Mich.) in a tweet. “He’s one of the most principled, consistent, and conservative members of Congress I’ve ever known. And unlike you, Mark has shown humility in his role and a desire to be a better man than he was the day before.”

Sanford did not immediately response to a request for comment, but in an interview Monday, he said that he had not spoken to the president since last summer, when members of the House Freedom Caucus were summoned to the White House to discuss efforts to repeal the Affordable Care Act. When asked whether he thought Trump would intervene in the race, Sanford looked at his watch.

“Not yet, but I guess we’ll find out tomorrow,” he said.