Republican presidential candidate Donald Trump speaks at a town hall event Thursday, Sept. 17, 2015, in Rochester, N.H. (AP Photo/Robert F. Bukaty)

The end of Wisconsin Gov. Scott Walker's (R) presidential campaign deprives the 2016 primary of an immaculately scripted candidate. Ask him how he'd take on the Islamic State, and Walker would tell you that he stood up to the unions that tried (and failed) to intimidate him. Ask him to peg the air speed velocity of an unladen swallow, and he'd say he stood up to the unions that tried (and failed) to intimidate him. When Walker gaffed, it was only because a reporter tried to push him off-script, and his refusal -- his attempt to get back to unions and intimidation -- veered into gibberish.

So it was notable that Walker used his withdrawal speech to ask the party to reject an unnamed -- and unscripted -- Republican frontrunner: Donald Trump. No candidate has suffered as many "gaffe" news cycles. Yet only recently has Trump started to dip a little in the polls. How? By being so confusing that voters cannot agree on what mistake he made.

The latest example might be the best. On Monday, shortly before the Walkerdammerung, Vox's Max Fisher opened fire on "the media" for "giving Trump a pass" over a gaffe about Muslims. "It has largely ignored Trump's exchange with the supporter about the need to 'get rid' of Muslims or at least Muslim 'training camps,' and has also ignored the latter's clear reference to a quasi-genocidal conspiracy theory," argued Fisher, before laying out how coverage of the Islamic State had indulged ignorant stereotypes about Islam.

It's true that some media focused on Trump's blase refusal to correct the supporter when he said that the president was not really American. But last week, when I asked the campaign what Trump heard from the supporter, spokeswoman Hope Hicks clarified: He heard the stuff about "domestic or foreign training camps." The befuddlement over what Trump actually heard and said bailed him out.

This keeps happening to the Republican front-runner. In fact, it helped launch his campaign. Three months ago, in New York, Trump suggested that Mexico was "sending" a criminal element across the border. "They’re bringing drugs," he said. "They’re bringing crime. They’re rapists. And some, I assume, are good people." Trump's tangled syntax made it sound like he said literally everyone coming across the border was a rapist -- which was not what he meant. That led to months of disconnect, exemplified by Fusion/Univision reporter Jorge Ramos, who framed many segments on the understanding that Trump was saying every border-crosser was a rapist.

"I agree with him on one aspect," Arizona sheriff Joe Arpaio told Ramos in one segment. "We do have rapists and murderers coming across the border. But not a majority."

"The vast majority of immigrants are not rapists," Ramos said.

Arpaio had essentially agreed with Trump's point -- but Fusion packaged the interview with the headline "even Joe Arpaio thinks Donald Trump has gone too far." He had not gone too far for Republican voters, because it was not even clear how far he'd done. The same thing happened in August, when Trump called in to CNN to say that Fox News debate co-moderator Megyn Kelly had "blood coming out of her eyes, blood coming out of her ... wherever," when she interrogated him. To pundits, and to RedState.com editor Erick Erickson -- who was about to host Trump at the site's annual conference -- it was clear that Trump was joking about menstruation.

"The campaign, when I talked to them, first refused to even acknowledge Trump had said anything other than 'bleeding out of her eyes,'" Erickson recalls. "When I sent them the transcript and audio, they called back and said he meant 'whatever,' though he might not have said it that way. Trump was just trying to move the conversation along. I asked them if they would publicly make that clarification and they refused, at which point I knew they weren’t being sincere about it."

Erickson disinvited Trump from the conference. Yet Trump's spin on the remark -- that he was merely incoherent, not misogynist -- won out with Republican voters.

The Incoherence Dodge has really only failed Trump once, and we might look back in a few months and realize once was all it took. When a Rolling Stone reporter heard Trump joke about Carly Fiorina's looks -- "can you imagine that, the face of the next president?" -- the candidate insisted that he was "talking about persona" and not whether she was attractive.

It was arguably the least substantive Trump gaffe. But it was hit at someone -- Fiorina -- who had hard-won credibility with Republicans. Whenever that's not present, Trump, to the bafflement of his rivals, can really say anything he wants.