President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE took aim at Rep. Mark Sanford Mark SanfordOn The Money: Business world braces for blue sweep | Federal Reserve chief to outline plans for inflation, economy | Meadows 'not optimistic' about stalemate on coronavirus deal Trump critic Sanford forms anti-debt advocacy group Republicans officially renominate Trump for president MORE (R-S.C.) hours before his primary race on Tuesday, endorsing his opponent with a reference to Sanford's much-publicized extramarital affair when he served as governor.

Mark Sanford has been very unhelpful to me in my campaign to MAGA. 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! — Donald J. Trump (@realDonaldTrump) June 12, 2018

Sanford's affair with Argentinian journalist Maria Belén Chapur in 2008 and 2009 nearly derailed his career after the then-South Carolina governor claimed he had been hiking the Appalachian Trail when in fact he was in Argentina with Chapur.

Sanford went on to divorce his wife in 2010.

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He will face off against Arrington, a state representative, in Tuesday's GOP primary for South Carolina's 1st District.

Arrington has also used Sanford's affair to attack him in the race, alluding to it in a campaign ad released last month.

“Bless his heart, but it is time for Mark Sanford to take a hike — for real this time,” Arrington says in ad.

Sanford is one of Trump's most vocal GOP critics and has publicly slammed his behavior and policies, including his travel ban, which he says "fanned the flames of intolerance."

The lawmaker also repeatedly called for Trump to release his taxes during the 2016 presidential race.

Some of Sanford's fellow members of the conservative House Freedom Caucus defended him on Twitter following Trump's slam.

Freedom Caucus Chair Meadows: "Mark Sanford has been a valued member of the Freedom Caucus & certainly has been a thoughtful member of congress. I am very supportive of his re-election efforts & passage of the tax reform package would not have been possible without his input" — Alex Moe (@AlexNBCNews) June 12, 2018

Arrington has capitalized on Sanford's criticism of the president.

“You can’t have a seat at the table in the Oval Office because you’ve offended the president numerous times,” she said earlier this month.

“You should have the wherewithal not to go on CNN and bash our president. Instead, work with the president, work with leadership to get done what we want.”

Sanford has never lost an election in South Carolina, serving eight years in the governor's mansion sandwiched by six terms in Congress.