But this is also a moment of truth for the Republican Party: The country is on a knife’s edge, with G.O.P. officials from state capitols to Congress choosing between the will of voters and the will of one man. In pushing his false claims to the limits, cowing Republicans into acquiescence or silence, and driving officials like Mr. Shinkle to nervous indecision, Mr. Trump has revealed the fragility of the electoral system — and shaken it.

At this point, the president’s impact is not so much about overturning the election — both parties agree he has no real chance of doing that — but infusing the democratic process with so much mistrust and confusion that it ceases to function as it should.

Under an unending barrage of fraud charges, voters might begin to question the legitimacy of elected officials from the rival party as a matter of course. And the G.O.P. risks being seen as standing for disenfranchisement and the undemocratic position that a high level of voting is somehow detrimental.

“What Trump is doing is creating a road map to destabilization and chaos in future years,” said Trevor Potter, a Republican who served as chairman of the Federal Election Commission in the 1990s. “What he’s saying, explicitly, is if a party doesn’t like the election result they have the right to change it by gaming the system.”