We are in the midst of yet another of Donald J. Trump’s self-inflicted spirals of terrible news. And with prominent Republicans saying they will back Hillary Clinton and others announcing this week that they won’t endorse Mr. Trump, there has been yet another round of speculation about how the party could get rid of him.

But it almost certainly can’t. And even if it could, it probably wouldn’t be worth the effort. Here’s why.

Under Republican Party rules, Mr. Trump is the only one who can take himself out of the race at this point. The only provision that exists for replacing a candidate nominated at the party convention, Rule 9, was written to apply only in the event of a candidate’s death or refusal to run.