One reason the falsehoods have flourished is the failure of Republicans who do not believe them to push back. Before the Jan. 6 hearings began, Republican leaders promised a robust “rapid response” effort to counter the narratives that would emerge.

But there has been no such pushback from the Republican National Committee or any other organization to revelations that Mr. Trump continued to pressure Mr. Pence to overturn the election results, even after having been told doing so was illegal.

No Republican leader offered a response to the testimony of retired federal appeals court Judge J. Michael Luttig, a revered conservative, who said on Thursday that Mr. Trump gave Mr. Pence an order whose execution would have prompted “the first constitutional crisis since the founding of the Republic.”

None bothered to counter the panel’s finding, revealed on Monday, that Mr. Trump and his campaign raised hundreds of millions of dollars from supporters based on the false pretense of massive election fraud, using money collected for an election defense fund that did not exist.