In a new interview with Larry King, veteran newsman Dan Rather defends Fox News from critics who say it’s little more than a media operation for the Republican Party.

“Do you ever think the thought that Fox News channel is an actual part of the Republican party?” King asks Rather.

After a pause, Rather says the criticism “goes too far.”

“I’ll say this about [Fox News CEO Roger Ailes]:” Rather says, ”he is a very good businessman, he’s very smart about television, and he built a network when I, for one, wasn’t at all sure he could do so. And has he used it to benefit the Republican Party, yes. The record is very clear on that. But is it a sole operative and propaganda machine for the party? I’d have to stop short of that.”

Ailes is the subject of a new unauthorized biography that is highly critical of the Fox News chief. In recent interviews, the author of the book, Gabriel Sherman, describes Fox News as a “political operation that employs journalists.”

The interview airs on “Politicking with Larry King” 9 p.m. ET Thursday night on RT TV as well as Hulu.com.