McConnell’s team “shoots the wounded on the battlefield as a matter of course,” says University of Virginia professor Larry Sabato. A former GOP leadership aide who has seen the McConnell operation up close sounds terrified. “They’re all killers,” he says, without a trace of humor in his voice. “These are not guys to be trifled with. They are burn it down, p*** on it, then blow it up kind of guys.”

And it’s not a secret. The New York Times reported that the National Republican Senatorial Committee (NRSC) was blacklisting a GOP ad firm, Jamestown Associates, for working with the Senate Conservative Fund (SCF), which is helping Bevin. Privately, McConnell aides acknowledge that it was McConnell who had Jamestown blacklisted for cutting ads that the SCF ran in Kentucky. McConnell’s former chief of staff, Josh Holmes, spoke to the Times, offering a dark analogy: “The SCF has been wandering around the country destroying the Republican Party like a drunk who tears up every bar they walk into. The difference this cycle is that they strolled into Mitch McConnell’s bar, and he doesn’t throw you out, he locks the door.” Holmes, who is now heading McConnell’s campaign committee, later confirmed on Twitter that his quote alluded to a scene in A Bronx Tale in which a group of mafiosos savagely beat members of a biker gang who vandalized their bar — a scene as violent as any in the movies.

In blacklisting Jamestown, McConnell has opened up a new front in what has become an open war between McConnell and Holmes, on the one side, and Heritage Foundation president Jim DeMint and SCF executive director Matt Hoskins on the other…

For McConnell, this is the direst threat of his career, as he’s now in a two-front war, with Bevin on one flank and Democratic challenger Allison Lundergan Grimes on the other. The wily incumbent is upping the ante, casting the fight as a battle for the future of the Republican party.