Many Republicans consider this strategy suicidal.
“This is the reason that Republicans didn’t regain the majority in 2010 and 2012,” said Josh Holmes, a former aide to Mr. McConnell who is president of Cavalry Strategies in Washington. “You had this for-profit, quote, unquote conservative crowd who found it much more entrepreneurial to challenge from within than to fight back against Democrats. And ultimately what happened in those two cycles is that Democrats won. Republicans exhausted their resources.”
Using attacks on Republican leaders like Mr. McConnell and Speaker Paul D. Ryan as a way to motivate voters on the right — and to raise money — is nothing new for groups that have tried for years to push Republicans to toe a harder, less compromising line. But to make such a senior leader of their own party the public face of a national campaign to unseat fellow Republicans represents a new level of hostility.
As Mr. Bannon looks to recruit Republicans to run in those seven states where Republican seats are up — Arizona, Mississippi, Nebraska, Nevada, Tennessee, Utah and Wyoming — he has asked them whether they will commit to a pledge not to vote for Mr. McConnell as leader. Those who refrain from making the pledge cannot win his endorsement, or the funding source that comes with it.
Many conservatives believe that Mr. Moore won in Alabama in large part because of the harsh criticism he leveled at Mr. McConnell and Republican leaders in Washington.
“Mitch McConnell was an albatross around Luther Strange’s neck, much like Nancy Pelosi has been used against Democrats,” said Ken Cuccinelli, president of the Senate Conservatives Fund, which often targets Republicans who are close to leaders like Mr. McConnell. “That is not going to change,” Mr. Cuccinelli added. “And that makes all of these folks vulnerable, so long as they stay on that team.”
On Wednesday, the leaders of groups that included FreedomWorks and the Tea Party Patriots presented Mr. McConnell with a list of their grievances. He had failed, they said, to do anything to stop illegal immigration, reduce the deficit, shrink the federal bureaucracy or cut off funding to Planned Parenthood. But their biggest grievance by far was the lack of movement toward repealing the Affordable Care Act, which they put squarely on his shoulders.
“Mitch McConnell had his chance. The entire Republican leadership had its chance. They have failed,” said Jenny Beth Martin, co-founder of the Tea Party Patriots.
The toxicity of Republicans in Washington is a problem that even those who are working to re-elect them acknowledge. “Now the answer to what is wrong in Washington is the Republican Congress,” Steven Law, president of the pro-McConnell Senate Leadership Fund, wrote in a memo after the Moore upset.
The prospect of incumbent Republicans fighting on two fronts — against insurgent candidates in states where they should be safe and against Democratic challengers in states where Mr. Trump is a liability — all while trying to pass a major tax bill does not seem to concern the conservatives who are calling for Mr. McConnell’s ouster. In fact, it seems to be something they welcome.
“It is time for you and your leadership team to step aside,” the leaders of the conservative groups wrote in a letter to the majority leader on Wednesday. “American is too good for you to lead it.”