I think it's really stupid for the Republican machinery in general to attack Comey. First, he's a Republican, and he represents a very real faction of NatSec oriented moderate Republicans that are a crucial part of their elite backers. Maybe they've decided those people don't matter because they'll vote Republican anyway, but I definitely wouldn't take that for granted.
Second, right now the Republican party is not involved in this scandal. Everyone directly connected to the potential scandal are all Trumpites with no real connection to the party as a whole. By choosing to own the scandal, they unnecessarily risk downside if it ends up costing them in terms of public opinion. And there's no upside, because if he is vindicated in some way, it's not going to cause the public to embrace him.
If I was the RNC, I'd want to go with "We believe the Special Counsel's investigation will vindicate the President's actions during and since the campaign. We remain focused on the important task of blah blah blah jobs blah blah blah fighting ISIS blah blah blah punching orphans."
Let it also be noted that I actually think Republicans are in a better position if Mike Pence [remember: he's the guy that Flynn lied to, he is the victim of the Russian conspiracy] is President, and while there's some interim pain, I would think they'd come out the other end and recover pretty quickly.
