“This is an effort by Mitch McConnell and his cronies to steal this election from the people of Alabama and they will not stand for it!” Mr. Moore wrote on Twitter on Thursday. “I’m gonna tell you who needs to step down,” he continued in another post, “that’s Mitch McConnell.”

But many Republicans believe that trying to remove Mr. Moore from the race or expel him from the Senate if he wins would further enrage the party’s restive base and kill the small-dollar fund-raising that both political parties rely heavily on. And it would provide the kind of raw, angry grass-roots energy that Mr. Bannon says he needs to achieve his goal of ensuring that Mr. McConnell is not the Republican leader a year from now.

“Roy Moore would be a thorn in the Senate G.O.P. leadership’s side, and they would be happy to expel him hoping to both dissuade others and put down the Bannon rebellion,” said Erick Erickson, the Christian conservative writer and radio host who has argued that the debate over Mr. Moore should be viewed in the context of the much larger and more pitched battle between the party’s establishment and anti-establishment wings.

Party leaders, Mr. Erickson added, “are not as interested in the long-term consequences.” They just want to send a signal by defeating Mr. Moore that the conservative insurrection can and will be crushed, he added. Writing on his website recently, Mr. Erickson said, “I don’t blame the Roy Moore voters for thinking people are out to get them because people really are out to get them.”

Mr. Erickson, like Mr. Bannon, did not initially support Mr. Moore when the primary for the Senate seat vacated by Jeff Sessions, the attorney general, was a three-way contest. In the first round of voting, it was Mr. Moore against Senator Luther Strange, who was appointed to the seat and was supported by Mr. McConnell, and Representative Mo Brooks, a conservative favorite who is much less unpredictable and polarizing. But after Mr. Brooks did not make the runoff, conservatives say, they rallied behind Mr. Moore because of what he represents to them: someone who is under attack from the same Republicans they believe have long tried to marginalize religious conservatives.

That sense of marginalization is real for many. A caller into Rush Limbaugh’s radio program on Tuesday expressed similar suspicions, saying he believed Mr. Moore’s ouster would be the beginning of a purge of the party’s right wing. “But my worry,” said the caller, who identified himself as Jim from Missouri, “is the so-called conservatives in Congress are going to fall prey to this and throw this man under the bus. And then they’ll forever set a precedent for getting rid of conservative people that we might try to elect.”