The question now is what those incumbents will do. Breitbart’s failure to take down McConnell and Ryan in 2016 should suggest to them it doesn’t have the juice Bannon thinks it has. But they may be running scared now and want to seek preemptive peace by kowtowing to Bannon.

What will that mean? It could mean a staged coup against McConnell in the Senate. It could mean a wholehearted embrace of Breitbart extremism on trade immigration and isolationism. It could mean the GOP in the Senate turns into what Bannon wants it to be without him ever having to fire a shot.