For Scott Walker, last week could have been magic. But—thanks to his struggles with immigration—it was doomed.

The headlines started beautifully: On August 18, he had a verbal tussle with a protester who heckled the Wisconsin governor’s soapbox speech at the Iowa State Fair.

“I am not intimidated by you, sir, or anyone out there,” Walker said to a heckler, according to CNN . “This is what happened in Wisconsin. We will not back down, we will do what is necessary.”

But that was before anyone asked about immigration.

Things get ugly for Walker—very ugly, quite fast—when he talks about immigration. It’s complicated his presidential bid, causing him headache upon headache. And some who know him say that a big reason his immigration struggles are perpetually messy just might be because he doesn’t necessarily buy into the things he’s saying.

The trouble last week began the day before the altercation with the protester, when MSNBC’s Kasie Hunt pressed the governor on his stance on birthright citizenship—should we end it?

“Yeah, to me it’s about enforcing the laws in this country,” he replied. This was Monday, August 17 . “And I’ve been very clear, I think you enforce the laws, and I think it’s important to send a message that we’re going to enforce the laws, no matter how people come here we’re going to enforce the laws in this country.”

It was a bit of a head-scratcher—did Walker really oppose birthright citizenship rights?

The story percolated, drawing more and more attention, and then things really got interesting Friday, when he told CNBC’s John Harwood that he was “not taking a position on it one way or the other.”

That, predictably, made things worse. So on Sunday, the governor went on This Week on ABC and said he doesn’t favor amending the Constitution to change birthright citizenship. Whew! Dizzying.

It’s a simple question, and answering it shouldn’t have been so hard.

But we are talking about Scott Walker.

Immigration has long tripped up the candidate. He’s found himself in awkward situation after awkward situation trying to explain how he moved from being a mild-mannered, business-friendly executive—uninterested in red-meat rhetoric about border fences or so-called anchor babies—to a presidential candidate bumbling through crowded fairgrounds while trying to get to Donald Trump’s right on the issue.

But to those who know him best, this shift isn’t that hard to understand.

Charlie Sykes, one of the most influential conservative talk-radio hosts in Wisconsin, estimates he’s interviewed Walker hundreds of times over the last 20 years. Sykes said there may be a very simple explanation for why Walker has had so much trouble talking about the issue: The governor doesn’t believe what he’s saying.

That’s right. Walker’s Breitbart-friendly, immigration-skeptical rhetoric on the issue is an innovation that seems to make the governor uncomfortable. Sykes said that though Walker’s official stances put him nearly as far right as Donald Trump on questions regarding birthright citizenship and the economic impact of legal immigration, his heart is elsewhere. Sykes said he thinks Walker has adopted this position to keep any other Republican candidates from getting to his right.

But that’s come with a cost: namely, it’s forced him to speak nativism, which isn’t his native language. And trying to become ideologically bilingual while bouncing betwixt campaign stops and squinting into national media spotlights has wrought unimpressive results.

“The immigration thing, I think has been a tricky issue for him because he wants to protect his right flank, although, intellectually, he’s always been very centrist on the issue,” Sykes said.

In late April of this year, the governor made headlines for saying that legal immigration could have hurt the wages of native-born Americans.

“In terms of legal immigration, how we need to approach that going forward is... to make decisions about a legal immigration system that’s based on, first and foremost, protecting American workers and American wages,” he said, via The Washington Post . “What is this doing for American workers looking for jobs, what is this doing to wages, and we need to have that be at the forefront of our discussion going forward.”

In that innocent, pre-Trump era, arguing that legal immigration could hurt the economy was highly unusual, even on the right. It was a case made primarily by Senator Jeff Sessions, an Alabama Republican, and by writers at Breitbart News.

Sykes said he was baffled to see Walker make common cause with them.

“I’d never heard him take those kinds of positions on immigration prior to maybe April,” he said, “because first of all, that’s not the kind of issue that he’s been terribly involved in. It’s not the wing of the party, it’s not the things he talks about.”

“I think the nativist rhetoric does not come naturally to him,” Sykes continued. “That is not his native tongue. That’s when a politician begins to stumble, when they’re speaking a language they’re really not that comfortable with.”

Sykes said close watchers of Walker always believed he sided with The Wall Street Journal and the Chamber of Commerce on immigration: that legal immigration benefits the economy, that rising tides lift all boats, etc.

“I was genuinely shocked when he started doing that Jeff Sessions stuff about visas for legal immigration,” Sykes continued, citing Walker’s newly expressed concerns about legal immigration levels. “I actually thought that might have been a misquote or something, one of these verbal tic misunderstandings. But no, that’s what he’s been saying. And I’ve never heard him as governor of the state talk about the negative role of legal immigration in creating jobs.”

So Walker’s new, Trump-friendly stance on immigration has put him in rhetorically unfamiliar waters.

Liz Mair, a consultant who was fired from the campaign after Iowa Republican leaders took issue with some of her policy stances , said she noticed the same thing.

“Scott Walker has a lengthy history that encompasses all but about the last six months of his entire political career of being strongly pro-immigration, and pro-comprehensive reform,” she said.‎ “No matter the supposed ‘incentives’ for doing it, it’s hard to sound like Jeff Sessions when your entire thought process surrounding an issue is and always has been radically different to Jeff Sessions’.”

She added, “It's also proving to be a dud with everyone but a few Breitbart staff; voters can spot a fraud a mile off, and Walker emulating Sessions on this issue correctly reads as fake.”

Before Walker was a born-again nativist, he went on foreign trade missions as governor—including to China—and led an effort to re-brand the state as “Wisconsin is open for business.”

“If people want to come here and work hard in America, I don’t care whether they come from Mexico or Ireland or Germany or South Africa or anywhere else, I want ’em here,” he said in a July 2013 meeting with The Wausau Daily Herald editorial board .

In that meeting, he even downplayed the need for more border security.

“[Y]ou hear some people talk about border security and a wall and all that,” he said. “To me, I don’t know that you need any of that if you had a better, saner way to let people into the country in the first place.”

And as Milwaukee County executive, he signed a letter calling for a pathway to legal status for undocumented immigrants living here.

But since then, he says he’s had an about-face. The governor now favorably compares his stance on immigration to Trump’s . And in March this year, he told Fox News Sunday’s Chris Wallace that his view “has changed. I’m flat out saying it.”

Sykes isn’t alone in thinking Walker’s nativist tack is just politics. Heritage Foundation scholar Stephen Moore told The New York Times in July that Walker told him over the phone that he was “not going nativist” and that he was “pro-immigration.” But apparently those assertions were problematic, because Walker’s aides — again, according to The New York Times —pressured Moore into recanting the comments ( conservative site Red Alert Politics reported that Moore still “stood by his beliefs that Walker was pro-immigration”).

On top of that, The Washington Post reported that one conservative billionaire, Stanley Hubbard, said he differed with Walker on birthright citizenship but would back him anyway as he doubted his zealousness on the issue.

“I got the feeling that he is not at all anxious to talk about taking away those rights,” Hubbard told the paper.

Walker has given all those doubters some reason for their doubt. In March, The Wall Street Journal reported that he told a group of New Hampshire Republicans in private that he favored a pathway to legal status and citizenship for undocumented immigrants.

All told, it’s a dicey issue for his campaign, according to Collin Roth, the managing editor of Right Wisconsin.

“It goes to the very heart of the rationale for his candidacy, of being a big bold decider—a guy who makes a decision, sticks with it, and goes with it—for him to be all over the place,” Roth said.