The debate, sponsored by Newsmax, will take place in Iowa on Dec. 27 and air on ION television. Rove added that few people are likely to watch the debate, which will be a "giant ego trip."
Republican presidential candidates Ron Paul and Jon Huntsman have already declined to participate.
"The Republican Party deserves a serious discussion of the issues so voters can choose a leader they trust to defeat President Obama and turn our economy around," Huntsman spokesman Tim Miller said, announcing Huntsman would not attend.
Paul's campaign also slammed the moderator choice as unserious.
“The selection of a reality-television personality to host a presidential debate that voters nationwide will be watching is beneath the office of the presidency and flies in the face of that office’s history and dignity,” Paul spokesman Jesse Benton said, predicting a "circus-like atmosphere" at the debate.