The nature of the right means that you can only double down on the crazy because of you aren't somebody else will. Sessions, as terrible of a person he is, got destroyed yesterday because he wasn't a total monster.
Romney is seen as somebody reasonable today but in 2012 he did really had to go to extreme in some regards because he was being accused of being a ''moderate'' during the primary. Romney just went far enough not to look totally crazy like Santorum and Gingrich.