Tim Scott defended fellow US South Carolina Republican senator Darline Graham’s knowledge of national security issues ahead of their state’s runoff election on Tuesday.

Graham, who was appointed to fill the Senate seat held by her brother Lindsey Graham after his sudden death in July, is in a Republican primary runoff against South Carolina congressman Ralph Norman. During a debate between the two on Tuesday night, Graham struggled to answer a question about US national security interests in Taiwan and the South China Sea.

“I’m just going to be honest here. I’m not that informed on national security,” she said during the debate. She added: “National security is not my thing.”

Scott tried to assuage concerns about her experience on Sunday when he was asked about Graham’s qualifications – and whether a US senator should have an understanding of national security issues.

“Well, the answer is yes. And she does,” he said during an interview on NBC’s Meet the Press. He went on to give an answer that did not detail any of her national security experience.

“The question we’re asking ourselves today is whether or not she is prepared to serve in the United States Senate and represent the people of South Carolina on the issues that are germane to the moment, with all the issues of the moment,” he said. “And is she prepared to hit those issues? She hits those issues spot-on.”

Graham held various public policy jobs in South Carolina – but never had run for or held public office before she was appointed to the Senate.

Beside Scott, Donald Trump has endorsed Graham – and he traveled to South Carolina on Friday to rally for her. The president also brushed off Graham’s answer on Friday.

“I watched that,” he said. “I thought it was a very honest answer, actually.”