So let's review. Brian is a fair weather believer with little or no actual strength to his convictions, Lois was right all along. The viewer should never take his ranting seriously. Therefore Brian must return home and activate the obligatory reset to the status quo, because living with the Griffins and being a liberal is just who he is! Except when it isn't!
.......yyyyyyyyyyyyyeeeeeaaaaahhhhh.
Ah but wait, Rush Limbaugh was in this episode! I was meant to ignore the logic and be amused by the guest star's very presence, allowing that to prop the whole mess up for me all by itself. My bad.
Good gags: Brian staring at the bag. Limbaugh saving Brian & the bit with the cold cut left in the book. The Scooby Doo skit, even though it's been done to death. Peter repeatedly switching sides during the dinner table argument. Stewie breaking the fourth wall to make fun of Fox for the entire idea.
On a meta scale though, this was dreadful.