On Tuesday, October 16, President Donald Trump started tweeting.

“The United States has strongly informed the President of Honduras that if the large Caravan of people heading to the U.S. is not stopped and brought back to Honduras, no more money or aid will be given to Honduras, effective immediately!” “We have today informed the countries of Honduras, Guatemala and El Salvador that if they allow their citizens, or others, to journey through their borders and up to the United States, with the intention of entering our country illegally, all payments made to them will STOP (END)!”

Vice President Mike Pence also tweeted:

“Spoke to President Hernandez of Honduras about the migrant caravan heading to the U.S. Delivered strong message from @POTUS: no more aid if caravan is not stopped. Told him U.S. will not tolerate this blatant disregard for our border & sovereignty.”

The apparent impetus for this outrage was a segment on Fox News that morning that detailed a migrant caravan thousands of miles away in Honduras. The caravan, which began sometime in mid-October, is made up of refugees fleeing violence in their home country. Over the next few weeks, Trump did his best to turn the caravan into a national emergency. Trump falsely told his supporters that there were “criminals and unknown Middle Easterners” in the caravan, a claim that had no basis in fact and that was meant to imply that terrorists were hiding in the caravan—one falsehood placed on another. Defense Secretary James Mattis ordered more troops to the border. A Fox News host took it upon herself to ask Homeland Security Secretary Kirstjen Nielsen whether there was “any scenario under which if people force their way across the border they could be shot at,” to which Nielsen responded, “We do not have any intention right now to shoot at people.”

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Pence told Fox News on Friday, “What the president of Honduras told me is that the caravan was organized by leftist organizations, political activists within Honduras, and he said it was being funded by outside groups, and even from Venezuela … So the American people, I think, see through this—they understand this is not a spontaneous caravan of vulnerable people.”

The Department of Homeland Security’s Twitter account “confirmed” that within the caravan are people who are “gang members or have significant criminal histories,” without offering evidence of any such ties. Trump sought to blame the opposition party for the caravan’s existence. “Every time you see a Caravan, or people illegally coming, or attempting to come, into our Country illegally, think of and blame the Democrats for not giving us the votes to change our pathetic Immigration Laws!” Trump tweeted on October 22. “Remember the Midterms! So unfair to those who come in legally.”

In the right-wing fever swamps, where the president’s every word is worshipped, commenters began amplifying Trump’s exhortations with new details. Representative Matt Gaetz of Florida wondered whether George Soros—the wealthy Jewish philanthropist whom Trump and several members of the U.S. Senate blamed for the protests against Supreme Court Justice Brett Kavanaugh, and who was recently targeted with a bomb—was behind the migrant caravan. NRATV, the propaganda organ of the National Rifle Association, linked two Republican obsessions, voter fraud and immigration. Chuck Holton told NRATV’s viewers that Soros was sending the caravan to the United States so the migrants could vote: “It’s telling that a bevy of left-wing groups are partnering with a Hungarian-born billionaire and the Venezuelan government to try to influence the 2018 midterms by sending Honduran migrants north in the thousands.” On CNN, the conservative commentator Matt Schlapp pointedly asked the anchor Alisyn Camerota, “Who’s paying for the caravan? Alisyn, who’s paying for the caravan?,” before later answering his own question: “Because of the liberal judges and other people that intercede, including George Soros, we have too much chaos at our southern border.” On Laura Ingraham’s Fox News show, one guest said, “These individuals are not immigrants—these are people that are invading our country,” as another guest asserted that they were seeking “the destruction of American society and culture.”

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In the meantime, much of the mainstream press abetted Trump’s effort to make the midterm election a referendum on the caravan. Popular news podcasts devoted entire episodes to the caravan. It remained on the front pages of major media websites. It was an overwhelming topic of conversation on cable news, where Trumpists freely spread disinformation about the threat the migrants posed, while news anchors displayed exasperation over their false claims, only to invite them back on the next day’s newscast to do it all over again.

In reality, the caravan was thousands of miles and weeks away from the U.S. border, shrinking in size, and unlikely to reach the U.S. before the election. If the migrants reach the U.S., they have the right under U.S. law to apply for asylum at a port of entry. If their claims are not accepted, they will be turned away. There is no national emergency; there is no ominous threat. There is only a group of desperate people looking for a better life, who have a right to request asylum in the United States and have no right to stay if their claims are rejected. Trump is reportedly aware that his statements about the caravan are not true. An administration official told The Daily Beast simply, “It doesn’t matter if it’s 100 percent accurate … This is the play.” The “play” was to demonize vulnerable people with falsehoods in order to frighten Trump’s base to the polls.

Nevertheless, some took the claims of the president and his allies seriously. On Saturday morning, Shabbat, a gunman walked into the Tree of Life synagogue in Pittsburgh and killed 11 people. The massacre capped off a week of terrorism, in which one man mailed bombs to nearly a dozen Trump critics and another killed two black people in a grocery store after failing to force his way into a black church.

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Before committing the Tree of Life massacre, the shooter, who blamed Jews for the caravan of “invaders” and who raged about it on social media, made it clear that he was furious at HIAS, founded as the Hebrew Immigrant Aid Society, a Jewish group that helps resettle refugees in the United States. He shared posts on Gab, a social-media site popular with the alt-right, expressing alarm at the sight of “massive human caravans of young men from Honduras and El Salvador invading America thru our unsecured southern border.” And then he wrote, “HIAS likes to bring invaders in that kill our people. I can’t sit by and watch my people get slaughtered. Screw your optics, I’m going in.”

The people killed on Saturday were killed for trying to make the world a better place, as their faith exhorts them to do. The history of the Jewish people is one of displacement, statelessness, and persecution. What groups like HIAS do in helping refugees, they do with the knowledge that comes from a history of being the targets of demagogues who persecute minorities in pursuit of power.

Ordinarily, a politician cannot be held responsible for the actions of a deranged follower. But ordinarily, politicians don’t praise supporters who have mercilessly beaten a Latino man as “very passionate.” Ordinarily, they don’t offer to pay supporters’ legal bills if they assault protesters on the other side. They don’t praise acts of violence against the media. They don’t defend neo-Nazi rioters as “fine people.” They don’t justify sending bombs to their critics by blaming the media for airing criticism. Ordinarily, there is no historic surge in anti-Semitism, much of it targeted at Jewish critics, coinciding with a politician’s rise. And ordinarily, presidents do not blatantly exploit their authority in an effort to terrify white Americans into voting for their party. For the past few decades, most American politicians, Republican and Democrat alike, have been careful not to urge their supporters to take matters into their own hands. Trump did everything he could to fan the flames, and nothing to restrain those who might take him at his word.

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Many of Trump’s defenders argue that his rhetoric is mere shtick—that his attacks, however cruel, aren’t taken 100 percent seriously by his supporters. But to make this argument is to concede that following Trump’s statements to their logical conclusion could lead to violence against his targets, and it is only because most do not take it that way that the political violence committed on Trump’s behalf is as limited as it currently is.

The Tree of Life shooter criticized Trump for not being racist or anti-Semitic enough. But with respect to the caravan, the shooter merely followed the logic of the president and his allies: He was willing to do whatever was necessary to prevent an “invasion” of Latinos planned by perfidious Jews, a treasonous attempt to seek “the destruction of American society and culture.”

The apparent spark for the worst anti-Semitic massacre in American history was a racist hoax inflamed by a U.S. president seeking to help his party win a midterm election. There is no political gesture, no public statement, and no alteration in rhetoric or behavior that will change this fact. The shooter might have found a different reason to act on a different day. But he chose to act on Saturday, and he apparently chose to act in response to a political fiction that the president himself chose to spread and that his followers chose to amplify.

As for those who aided the president in his propaganda campaign, who enabled him to prey on racist fears to fabricate a national emergency, who said to themselves, “This is the play”? Every single one of them bears some responsibility for what followed. Their condemnations of anti-Semitism are meaningless. Their thoughts and prayers are worthless. Their condolences are irrelevant. They can never undo what they have done, and what they have done will never be forgotten.