The latest evidence of McConnell's toxicity among Republican voters came in a West Virginia Senate debate this week. All three Republican candidates were asked to raise their hands if they supported McConnell for majority leader. None did.
"I'm not the product of the liberal establishment," state attorney general Patrick Morrisey said. "I think that's why you're seeing all the conservatives come out for me. I'm going to make the right decision after we get through the general election."
Rep. Evan Jenkins praised McConnell for shepherding Neil Gorsuch's Supreme Court nomination through the Senate but said: "Mitch McConnell hasn't even asked for my support. I think it's way too premature."
Don Blankenship, the coal baron who spent a year in prison on charges connected to a mine accident that killed 29 people -- and who this week labeled McConnell "Cocaine Mitch" in a shot at McConnell's father-in-law's shipping company -- ducked behind his podium.
"He interferes with elections all over this country. He's interfering with this election," Blankenship said, complaining about groups with ties to McConnell spending against him ahead of Tuesday's primary.
The balks by Jenkins and Morrisey were the latest evidence that mainstream Republicans -- not just anti-establishment crusaders -- don't want to get too close to McConnell.
Asked about how Republican candidates should approach McConnell, his allies often point to a McConnell interview with Fox News last year.
"Look, I'm not going to be on the ballot on any of the states, and I don't think the candidates who are running need to take a position on me," he said at the time.
Republicans in McConnell's circle said supporting the Kentucky Republican won't be a prerequisite to get the financial backing of McConnell-aligned forces -- the National Republican Senatorial Committee and the Senate Leadership Fund super PAC -- this fall.
The answers are almost identical to Democrats' responses when asked about House Minority Leader Nancy Pelosi.
Pelosi's allies frequently point to the inclusion of candidates who have pledged to oppose her for speaker -- a job she told The Boston Globe this week she still wants -- in the Democratic Congressional Campaign Committee's "Red to Blue" list of top recruits as evidence that she doesn't mind being thrown under the bus.
In both McConnell and Pelosi's cases, aides and allies appear to have decided that keeping or winning a majority is the only priority -- and everything else can be sorted out after November's midterm elections.
McConnell began emerging as a flashpoint in last fall's Alabama Senate special election, when the Senate Leadership Fund -- the McConnell-aligned super PAC that spends tens of millions of dollars to elect Republicans -- pumped millions into the race in an attempt to keep Roy Moore from winning the primary.
Former White House chief strategist Steve Bannon saw Moore as the first of an insurgent slate of anti-McConnell candidates that would defeat the establishment's preference across the map in 2018.
But Bannon's maneuvering came at a time the GOP base was furious over its congressional majorities' failure to repeal former President Barack Obama's signature health care law. Since then, McConnell has delivered victories on tax reform and in difficult confirmation battles. And Bannon has faded from the political forefront after the publication of a book in which he made critical remarks about Trump and other members of the administration.
Still, McConnell has remained the chief target of conservative outsiders challenging establishment-backed candidates in several Senate primaries.
In Wisconsin, a super PAC backing Kevin Nicholson in the GOP primary to take on Democratic Sen. Tammy Baldwin called on Nicholson's opponent, state Sen. Leah Vukmir, to oppose McConnell.
In Arizona, former state Sen. Kelli Ward has used Rep. Martha McSally's support from McConnell-aligned forces to label her out of touch with the GOP grassroots.
In Mississippi, state Sen. Chris McDaniel's campaign to unseat newly-appointed Sen. Cindy Hyde-Smith in a November jungle contest slammed McConnell in a March statement announcing he was entering the race.
"Mitch McConnell wants to hand-pick our next senator. I