Fox Business Network has apologized for re-airing an interview Saturday in which a guest alleged that the migrant caravan was being funded and directed by the George “Soros-occupied State Department." The comment, originally made by Judicial Watch head Chris Farrell and broadcast Thursday on Lou Dobbs’s show, took on a new level of crassness after the alleged shooter in the worst attack on Jewish Americans in history earlier Saturday was discovered to have promoted theories about the caravan being a Jewish plot.

But while the re-airing was rendered more than intemperate by new events, the conspiracy theory had been fertilized for weeks — often on Fox’s airwaves and with the help of the Trump family and its chief congressional allies. While such theories previously tended to lurk beneath the surface, potentially going viral on Facebook but otherwise being treated with suspicion and derision in polite society, they’ve increasingly found their way into the mainstream, thanks to some willing conduits.

The Washington Post’s Joel Achenbach has a big new story on how the Soros/caravan conspiracy theory pulls off the trifecta of weaving together “anti-Semitism, fear of immigrants and the specter of powerful foreign agents controlling major world events in pursuit of a hidden agenda.”

What’s as notable is how concern about promoting theories that may touch on those things is no longer so taboo. The idea that Soros, a wealthy, liberal Jewish donor, was funding the caravan in fact dates to the last time a caravan was headed to the U.S.-Mexico border in April. But while it had a difficult time getting beyond the pages of Infowars back then, this time it had some Republican congressmen, cable-news talkers and a president’s son to push it.

The theory began proliferating in mid-October in the form of questions about who was funding the latest caravan — without invoking Soros specifically.

“I want to talk a little bit about who is funding the caravan,” Fox News’s Laura Ingraham said Oct. 16. She noted that the Honduran “foreign ministry spokesman cited political sectors as culpable — unidentified political influences. Somebody is funding these caravans.”

On Oct. 17, Rep. Matt Gaetz (R-Fla.) — a Trump ally with a fondness for deep-state conspiracy theories — fingered possible culprits that included Soros.

“BREAKING: Footage in Honduras giving cash 2 women & children 2 join the caravan & storm the US border @ election time,” Gaetz tweeted. “Soros? US-backed NGOs? Time to investigate the source!”

President Trump soon tweeted the accompanying video (which was of Guatemala) without Gaetz’s Soros reference, and it has now been viewed more than 2 million times. “Can you believe this, and what Democrats are allowing to be done to our Country?” Trump said.

Gaetz’s tweet got a “like” from Donald Trump Jr.

On Oct. 18, Trump Jr. liked a tweet from conservative actor James Woods making an even bolder claim: That the caravan was an “election trick" that amounted to “Soros nonsense."

Gaetz appeared on Fox Business’s “Kennedy" that day, where the host noted he was getting “pushback” for the tweet and asked him about it. The host provided no pushback of her own, though, when Gaetz failed to provide any real evidence.

LISA KENNEDY: So the president has been busy on Twitter and you have as well. You’ve gotten a lot of pushback for that tweet claiming that George Soros was paying Hondurans to get on a caravan.

GAETZ: I didn’t make that claim. I post that question in the basis for that, Kennedy, is that Judicial Watch and other organizations have seen a fusion between some of the George Soros-based left-leaning political groups and some of the NGO’s and specifically the Balkans was an area of the world where there seem to be strong evidence of that fusion. Here, President Trump undoubtedly got a win, but it’s the drug cartels that really lose.

They benefit greatly when you have a mass migration of people that makes it very difficult to ascertain who is legitimate, who is illegitimate, who is dangerous, and who may be safe. And I think that this is a real strengthening moment for the security of the region, and definitely a good demonstration of the president’s negotiating skills.

By Oct. 19, the theory became even bolder. NRATV correspondent Chuck Holton declared that “the real story here is the nexus we’re finding between left-wing groups from the United States, Soros-funded groups in Latin America and the Venezuelan government.” He added, “It’s telling that a bevy of left-wing groups are partnering with a Hungarian-born billionaire" — Soros — "and the Venezuelan government to try to influence the 2018 midterms by sending Honduran migrants north in the thousands.”

That day, Fox Business’s Maria Bartiromo brought up the theory of her own volition — and was begged off by her guest, Axios Editor in Chief Nick Johnston, who rightly noted it was a baseless “conspiracy theory”:

BARTIROMO: I mean, this is no coincidence, right? I mean who do you think is behind these caravans? A lot of speculation that it was George Soros. Do you believe that?

JOHNSTON: I do not. I am not a conspiracy theorist on how these people are sort of migrating their way up from the Central America and up to Mexico.

Gaetz was on Martha MacCallum’s Fox News show that night where she, to her credit, pressed him. “That was not accurate, correct?” she asked of his tweet. She noted that those handing out the small sums of money were likely “local merchants or organized crime” trying to ingratiate themselves rather than people funded by Soros. Gaetz didn’t back off his theory, though, and it was allowed to end as an agree-to-disagree. MacCallum even asked Gaetz to speculate as to whether there was “any connection whatsoever to our impending midterm election.”

By Oct. 22, with the theory raging on social media and becoming a focus of Infowars, Rep. Louie Gohmert (R-Tex.) appeared on Fox News and started talking about the funding of the caravan. The host tried to move the interview along, but Gohmert returned to it later. “I can’t help but think the Democrats — perhaps Soros — may be funding this, thinking it’s going to help them,” he said.

American Conservative Union head Matt Schlapp brought the theory — in the form of more supposedly innocent questions — to CNN that day. Schlapp didn’t directly link Soros to the caravan, but he suggested Soros was responsible for “chaos at the southern border”:

SCHLAPP: Who’s paying for the caravan? Alisyn, who’s paying for the caravan? I’d like to know. I think you should put a reporter on it. Who’s paying for it? You think --

ALISYN CAMEROTA: Matt -- oh, we have a reporter on it. Let me answer your question --

SCHLAPP: Let me ask, do you think this is spontaneous?

CAMEROTA: No, you asked me a question, let me answer it. We have journalists along the way. This is not -- no one is paying for the caravan. Poor people are marching 2,700 miles, Matt --

SCHLAPP: No. Nope.

...

CAMEROTA: Matt, you don't -- yes, you don't think that they are motivated because of the conditions in their country?

SCHLAPP: I think -- what I think is wonderful about them is they know America is a better place to live, and I think it’s a better place to live as well. One reason it’s a better place to live is that we are a nation of laws and you have to follow the law, and unfortunately, because of the liberal judges and other people that intercede, including George Soros, we have too much chaos at our southern border.

On Tuesday, Trump Jr. was back on the case, calling the caravan an “obvious political stunt."

Dobbs was on the case, too, not attacking Soros by name but citing the “Radical Left’s” role in a Twitter poll to his followers.

On Thursday, Farrell first made his comment on Dobbs’s show, with Dobbs letting it pass unchallenged. On Friday, Cesar Sayoc was arrested and charged with mailing postal bombs to more than a dozen Trump antagonists, including Soros, whom he had attacked repeatedly on social media. On Saturday, Robert Bowers allegedly killed 11 people at a synagogue in Pittsburgh. He has a similar paper trail, including linking the caravan to Jewish interests.

Suddenly, the Soros conspiracy theories were no longer welcome.