The proposed debate would have been held in Pennsylvania and moderated by Fox News anchors Bret Baier and Martha MacCallum.

“I am not surprised by this development because I feel that she knows it is very difficult, at best, for her to defend her record setting Flip-Flopping on absolutely everything she once believed in, including her statements that THERE WILL BE NO FRACKING IN PENNSYLVANIA and her HORRIBLE Performance on the Border,” Trump wrote on his social media platform Truth Social.

https://www.foxnews.com/politics/trump-says-kamala-harris-not-participate-fox-news-debate-sept-4