No, he’s not saying the president is really a Democrat. And he never actually used the M-word.
Maybe that’s because Utah’s junior senator hasn’t read Isaac Asimov’s Foundation Trilogy. Or maybe he has but, because it’s old and has not yet been a movie, he assumed that we didn’t know it and that it would take too long to explain.
The Mule is a character in Asimov’s classic series of novels that, when I was reading them, consisted of three books, “Foundation," (1951) “Foundation and Empire" (1952) and “Second Foundation" (1953).
After I moved on to other types of literature (biographies mostly, far too few novels), Asimov added four more books, two that come before the original trilogy and two that come after.