Republican presidential candidate Nikki Haley on Thursday tried to brush aside her recent comments about Texas possibly seceding from the union.

The former South Carolina governor first raised eyebrows on the subject Wednesday during a radio appearance, in which she discussed Texas’ standoff with the federal government over the state’s right to put up razor wire fencing along the southern border.

“If Texas decides they want to do that, they can do that. If that whole state says, ‘we don’t want to be part of America anymore,’ I mean, that’s their decision to make,” she told host Charlamagne tha God on his “Breakfast Club” show, when asked about the possibility of Texas leaving the union.

Similar secession efforts in the 1800s, including one in her home state of South Carolina, infamously set off the American Civil War. Shortly after the war’s conclusion, the U.S. Supreme Court ruled that the union is “indestructible,” and the court’s justices have remained firm on that.

When asked about her comments Thursday during a Fox News appearance, Haley downplayed her remarks.

“It’s not about secession,” she said. “Nobody’s going to do that. That’s not what people are talking about. What they are talking about is why isn’t the president there, keeping Texans safe.”

But this week wasn’t the first time that Haley claimed states had the right to secede. When asked about it in 2010 during her gubernatorial campaign, she replied: “I mean, the Constitution says that.” Constitutional law experts disagree.

It’s also not the first time Haley’s gotten tripped up on Civil War history in recent weeks. In December, Haley neglected to mention slavery when someone asked her about the war’s causes at a town hall event. Instead, she said it had to do with “the freedoms of what people could and couldn’t do.” When the questioner told her he was “astonished” she didn’t mention slavery, she replied: “What do you want me to say about slavery?” before abruptly moving on to another question.

Haley is the last viable challenger to former President Donald Trump in his bid for the GOP presidential nomination. She’s currently polling at about 18% support to Trump’s 72%.