For the past year, every effort by Republican leaders to topple Donald J. Trump has met with embarrassing failure. Yet, according to published reports, jittery insiders are considering still another way to detach the Trump brand from the party of Lincoln and to remove his name from the ballot by fiat. There is a better option, one that can avoid an ugly, and likely futile, confrontation and help both Mr. Trump and his party save face. All eyes must now turn to the unassuming governor of Indiana to do what must be done.

I say this not as a member of the so-called Never Trump faction of my party. Though Mr. Trump was not my first choice for the nomination, I found his attack on the established order appealing at times, even entertaining, and respected the wishes of the clear majority of Republican primary voters. Americans long have been entranced with the idea of the political outsider who puts self-interest aside to battle Washington’s wrongdoers and set things right. But in recent weeks — indeed, months — the pitfalls of political outsiderdom have become plain.