WASHINGTON >> As Republicans try to move past the furor that Donald Trump provoked with his attack on a Mexican-American judge, party leaders are finding themselves in the unpleasant position of asking yet again just how far is too far — and what, if anything, they can do to keep Trump in check.

Some lawmakers, senior members of the Republican National Committee and delegates to the party’s convention next month in Cleveland acknowledged in interviews this week that another disruptive self-inflicted crisis would force the party to begin seriously looking at ways to deny Trump the nomination.

So far, discussions of a renewed dump-Trump drive have taken place only among the factions of the party that are openly opposed to Trump, and they have failed to gain much support.

But Trump’s suggestion that Judge Gonzalo P. Curiel’s Mexican heritage should disqualify him from hearing a lawsuit against Trump University has reawakened talk of hatching a convention coup — a complicated and nearly impossible measure of last resort that has no precedent in modern Republican politics.

Sen. Bob Corker of Tennessee, the chairman of the Foreign Relations Committee and one of Trump’s most unapologetic backers on Capitol Hill, suggested this week that Trump had “a crucial two- or three-week period” to smooth out his rougher edges or put his nomination in jeopardy.

Stopping Trump at this point could prove additionally difficult, however, because he has quietly filled the most important convention committees — those that will determine the rules and platform — with delegates loyal to him.

Initially seen as not having a strong delegate whip operation, Trump can now count on about half the seats on the platform and rules committees, according to Republicans who have been tracking delegate selection. This is a major turnaround from two months ago, when Sen. Ted Cruz’s campaign was sweeping the delegate contests.

Conflicting impulses are at play. Republicans have been reluctant to openly encourage a challenge to Trump at the convention for fear of hopelessly splitting the party. But they are not discouraging the idea, either, as their patience with Trump’s erratic and offensive behavior wears thin.

A Republican National Committee spokesman declined to comment Thursday on calls to push Trump aside.

The most prominent voice to call for Trump’s ouster since his attack on Curiel has been that of Hugh Hewitt, a talk-radio host who is respected in conservative circles but has no role in the nomination process. On his show Wednesday, Hewitt advocated opening the convention to let the delegates decide the nominee because ignoring Trump’s flaws, he said, was like “ignoring Stage IV cancer.”

But the more resigned responses from party leaders like Rep. Paul D. Ryan, the speaker of the House, and Sen. Mitch McConnell, the Senate majority leader, signaled what many more Republicans have concluded: For better or worse, they are stuck with Trump.

“I think it would tear the party apart if we started changing rules,” said John Whitbeck, the chairman of the Virginia Republican Party and a delegate to the convention. “Our voters have spoken,” he added.

Whitbeck said that he had spoken with aides to Trump on Wednesday and that they seemed unfazed. “They do not believe that this is something that’s going to have an impact on the race,” he said. “And if they’re correct, we’ll just have to wait until the next controversial thing he says. And there will be other things. This guy just doesn’t care.”

The talk of forcing Trump from the ticket presumes something many Republicans are so far not willing to concede: That he is a lost cause whose self-destructive tendencies will make it impossible for him to beat Hillary Clinton, the presumptive Democratic nominee.

Party leaders — most notably Reince Priebus, the chairman of the Republican National Committee, and Ryan — have seemed eager to forgive Trump and move on. Several Republicans said this week that a statement Trump issued Tuesday afternoon, in which he attempted to explain his remarks about the judge, did buy him some goodwill. Preibus, for one, praised Trump late Tuesday, saying his speech that night amid the uproar over the judge was “exactly the right approach and perfectly delivered.”

Republican leaders are also unwilling to be seen as nullifying the results of a five-month nominating process in which Trump received more than 13 million votes, a record for a Republican primary contender. But their reasons may have more to do with simple realism than with lofty principles: For much of the last year, Republican elites have proved incapable of reeling Trump in, let alone of blocking his path.

Once Trump became the presumptive nominee last month, party officials more or less fell in line. Even Ryan came around, announcing last week that he would support Trump — just as Trump, it turned out, was unloading on Curiel.

One other obstacle confronts the never-say-die “Never Trump” crowd: No candidate of any stature has stepped forward to challenge Trump at the convention.

“Until somebody gets courage, it doesn’t matter,” said Curly Haugland, a member of the convention Rules Committee from North Dakota who has argued that delegates should vote their consciences in Cleveland — a position that puts him at odds with the leadership of the Republican National Committee.

Without a candidate, Haugland added, all talk of a contested convention is meaningless. “In order to have a contested convention,” he said, “we need to have contestants.”

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