The Republican leader is aiming to thwart Rep. Mo Brooks and former state Supreme Court Chief Justice Roy Moore in a special election in Alabama next month. Both men are campaigning against McConnell as a despised symbol of the establishment — and both would exacerbate his already stiff challenge wrangling his GOP Conference.

McConnell is responding in kind. His super PAC is set to spend much as $8 million to boost his favored candidate, recently appointed Republican Sen. Luther Strange. McConnell has activated his sprawling donor network and pressed the White House for more resources. And the National Republican Senatorial Committee, the Senate GOP campaign arm McConnell controls, has warned consultants they’ll be cut off from future work if they assist Strange’s opponents.