With speculation about whether he may defect from the Democratic party swirling around him, US senator John Fetterman described himself seemingly unintentionally as a “lifelong Republican” during a fireside chat in Texas over the weekend.

Fetterman made the comment when someone listening to him speak with CBS News political correspondent Major Garrett at the Texas Tribune Festival on Saturday asked the Pennsylvania senator why he had not become an independent.

“Because I’m a lifelong Republican,” Fetterman replied. Garrett promptly corrected him by saying, “Democrat,” as Fetterman raised a hand and shook his head in disbelief.

“That’s a moment right there that’s clippable, ladies and gentlemen,” Garrett said amid laughter from the audience. “Go, go, go – internet, spin wildly! Wildly spin, internet!”

Fetterman then remarked, “Yeah – I guarantee you that’s going to break through. That’ll get … clipped – yeah. I’m a lifelong Democrat, though, and that’s … the point.”

Social and news media commenters quickly seized on video of Fetterman’s gaffe, with more than one characterizing it as a Freudian slip.

Fetterman has drawn questions over his loyalty to the Democratic party after joining Republicans in opposing his party’s efforts to end the US war with Iran as well as to cut off military aid to Israel, which has been accused of committing genocide in Gaza.

He also appeared in a video praising Republican Pennsylvania US senator Dave McCormick at a convention held by the latter’s party in Dallas on 9 September.

Fetterman – who was elected to the US Senate in 2022 – has denied that he intends to defect to the Republican party. He has said he would only abandon the Democrats party if they became “the anti-Israel party”.

“I’m not going to be a Republican,” Fetterman told a reporter at the US Capitol in a video published online by CSPAN on 15 September. “Why can’t you guys just wait till the midterms? And if I turn a Republican, then I’ll be a liar.”

At the Texas Tribune Festival on Saturday, Fetterman expressed his belief that it was “entirely possible” for the Democratic party to clinch a majority in the Senate during the federal midterm elections in November, with Republicans being predicted to lose seats in Congress. But he declined to indicate with whom he may side if he ends up holding a tie-breaking vote on any given issue in the 100-seat Senate after the midterms.

“Let’s revisit after the midterms, and let’s see what happens – you know – if I happen to be 51,” said Fetterman, who was elected to the US Senate in 2022. “I don’t know.”