Longtime South Carolina Rep. Joe Wilson (R-SC) on Thursday endorsed Katie Arrington, the Trump-backed challenger to his congressional colleague Rep. Nancy Mace (R-SC).

Wilson, who’s been a member since 2001, took an unusual step on Thursday by intervening in a Republican primary in his own state by endorsing Arrington, making his endorsement a bigger deal in the primary.

Usually, members of Congress either do not intervene in the primaries of members from their own party in their state, or they line up behind the incumbent.

The congressman told The State newspaper that he is backing Arrington — a former lawmaker who also formally worked for the Department of Defense — because she is “a proven fighter” that holds conservative principles.

Rep. Joe Wilson (R-SC) speaks to a crowd at Sen. Lindsey Graham’s election night watch party on November 3, 2020, in Columbia, South Carolina. (Sean Rayford via Getty Images)

“As murderers and enemies of freedom grow emboldened by the feeble leadership of the Biden Administration, Washington needs more people who understand the significant implications of a weak America on the world stage,” Wilson told The State. “That’s why I am endorsing Katie Arrington for Congress in South Carolina’s 1st district.”

“Katie is a proven fighter for our conservative principles of limited government with expanded freedom which provides for a strong national defense and the safeguarding of our border,” He added. “I support Katie Arrington because I know she will make a difference working for the families of South Carolina.”

Arrington told The State in a statement that she “could not be more honored” to have the congressman’s support. A source also told the publication that he plans on holding a fundraiser for her.

Arrington, who called the congressman “a fearless fighter for the people of South Carolina,” said, “I am grateful to have his endorsement, and I look forward to working with him to advocate for the people of our great state.”

As a freshman lawmaker, Mace is taking on two challengers after being at odds with former President Donald Trump. Arrington has been the more prominent challenger, gaining support from Trump and now Wilson.

Rep Nancy Mace (R-SC) speaks with reporters after voting in the affirmative to hold former Trump adviser Stephen Bannon in criminal contempt at the U.S. Capitol Building on October 21, 2021, in Washington, DC. (Anna Moneymaker/Getty Images)

Jacob Bliss is a reporter for Breitbart News. Write to him at jbliss@breitbart.com or follow him on Twitter @JacobMBliss.