The constitutionality of the fairness doctrine is a bit murky. The fairness doctrine has been in and out of the Supreme Court many times and some of these courts decided that it is constitutional and others decided that it is unconstituitional. Look it up on Wikipedia for more info.
Either way, if the Democrats decide to try to reintroduce the fairness doctrine, the Supreme court will have the final say in the matter, not congress. So don’t worry about it.

Personally, I can’t tell if the fairness doctrine is constitutional or not, but the most recent supreme court decision on the issue decided that it is not constitutional, so I’m happy to just go along with that decision. It’s not my business if people want to be lied to by Limbaugh without a voice of reason to call him out on his BS.

Its funny that you quote the first amendment considering that, traditionally, Republicans find just about every other portion of this ammendment to be worth discarding, including freedom of the press. (school prayer, flag burning, profanity, “free speech zones” )