The divergent reactions to the horrifying massacre of 11 Jews in a Pittsburgh synagogue are not about left vs. right. They are about logic vs. delusion.

Here are the incontrovertible facts. Alleged terrorist Robert Bowers voraciously consumed and posted alt-right conspiracy theories. These included some that have been promoted (and are still being promoted) by President Trump: a dangerous “migrant caravan” is headed towards Texas; there are gang members and ‘Middle Easterners’ in it; liberals do not love our country and support “open borders”; the media is the “enemy of the people.”

Bowers also noted, accurately, that the Hebrew Immigrant Aid Society supports refugees and was hosting a nationwide “Refugee Shabbat” at many synagogues, including Tree of Life Synagogue in Pittsburgh.

And of course, he believed in odious anti-Semitic conspiracy theories. Some of these have been promoted by Trump’s inner circle (George Soros’s role, for example), others disavowed. Certainly, Trump himself has condemned anti-Semitism in the harshest possible terms.

But the anti-immigrant lies, the anti-Muslim lies, the anti-black lies, the anti-Semitic lies, and the anti-media lies are all part of the “package deal” of right-wing American populism. And it seems that most of the alt-right believes in the whole package.

That’s why, in the wake of the attack, figures from across the political spectrum—especially in the Jewish community—have rightly assigned responsibility to Trump and his avowedly nationalist movement.

Former Director of the Anti-Defamation League Abe Foxman, no left-winger (especially on Israel,) called Trump “a demagogue” and a “threat to American democracy.” His successor, Jonathan Greenblatt, did not use Trump’s name in his recent New York Times op-ed, but did say “If your candidate is attacking George Soros or the “globalists,” or a member of Congress from your party is embracing Holocaust deniers, you must stand up and tell them to stop.” Not a single member of Congress, Democrat or Republican, accompanied Trump on his visit to Pittsburgh.

And when Trump got there, thousands of people marched in the Squirrel Hill neighborhood in two separate protests organized by Jewish organizations, with signs like “President Trump: You are not welcome in Pittsburgh until you cease your assault on immigrants and refugees.”

This is not antifa or Black Lives Matter. This is not Bernie Sanders. This is the American and Jewish mainstream.

In response to the protests, Trump tweeted “Small protest was not seen by us, staged far away. The Fake News stories were just the opposite-Disgraceful!”

In one tweet, Trump thus managing to tell a lie, make the story about him rather than the victims, and spread the very hatred and conspiracy-mongering (this time of the media) that causes such tragedies to take place.

This is all common sense—or should be.

On the Israeli and American right, however, delusion has taken hold. We are hearing, again and again, the same myths which defy common sense. Such as:

1. It’s wrong to politicize this attack.

In fact, Robert Bowers politicized the attack by providing explicit, political reasons for carrying it out. We’re just trying to understand where he got those ideas from. Understanding the causes of things is what smart people do.

Besides, everyone politicizes attacks. For example, Rabbi Shmuley Boteach called out that noted anarchist bomb-thrower Paul Krugman for “politicizing” the tragedy. Yet Boteach himself wrote shortly after the attack that it was the product of “a delegitimization and demonization of Israel.” Not only is that also “politicizing” the attack; it is absurdly false. Bowers explicitly mentioned Jews, immigration, and multiculturalism—not Israel.

2. Only the terrorist is responsible.

Of course, only Bowers is legally responsible for his own actions. But responsibility isn’t black and white; there are shades of gray, contributing factors, and context. The point is that Trump’s movement created the conditions for terrorists like Bowers to thrive, and thus bears responsibility.

Normally, right-wingers have no problem holding leaders responsible for their followers’ actions. Benjamin Netanyahu holds the leaders of Hamas, Islamic Jihad, and even the Palestinian Authority responsible for terrorist attacks against Israelis—as he should. Trump held Black Lives Matter responsible for the murder of police officers in Dallas by a black militant who said it was payback for cops killing black men. For heavens sake, Republicans blame video games and Hollywood for gun violence (anything but guns, of course).

So why not here? Maybe Trump is responsible or maybe he isn’t, but everyone knows that people are influenced by leaders, ideologies, and media—conservatives especially. Why is this instance different?

3. Trump can’t be an anti-Semite because Ivanka and Jared.

First, the mainstream claim is not that Trump is personally anti-Semitic. The claims are that he enrages and enflames a nationalist movement that is largely anti-Semitic, that he fails to condemn white supremacists, that his conspiracy theories encourage more conspiracy theories as well as distrust and rage, and that his team frequently retweets and otherwise supports known anti-Semites. Anti-Semitism has gone up 60 percent on Trump’s watch—is that just a coincidence? And why hasn’t Trump done anything about it? Why has his administration decreased surveillance of right-wing and anti-Semitic organizations?

These aren’t rhetorical questions. They have answers: because the white supremacists are part of the Trumpist base—and their evil isn’t black-or-white either. There are shades of gray from ‘Make America Great Again’ to birtherism to racism to white nationalism. Trump doesn’t attack these people because they are his people.

Oh, and saying Trump can’t stoke anti-Semitism because his daughter is Jewish is like saying Trump can’t stoke anti-immigrant hatred because his wife is an immigrant. Care to make that claim?

4. The left is being divisive.

First, this isn’t “the left.” This is the center, left, mainstream, and sensible right. Second, there’s plenty of divisiveness to go around. For example, right-wing darling David Horowitz told his 57,000 Twitter followers that “The Jews who protested the president's trip to Pittsburgh to pay his respects to their slaughtered brothers and sisters are a disgrace to Judaism, and active abettors of the forces determined to finish the job that Hitler started.”

Third, progressives and moderates wouldn’t have to be so vocal if Trump would show an ounce of remorse, reflection, or responsibility, instead of insisting he is 100 percent not responsible in any way, shape or form.

Most importantly, whatever division is coming from the left pales in comparison from what Trump himself has said since the massacre. He has pandered to right-wing zealots by floating the subject of “birthright citizenship.” He has continued to tell lies about the “migrant caravan” and immigrants in general. He has increased, not decreased, the incendiary fire of his nationalist rhetoric.

Even if “the left” were sowing division, Donald Trump is doing so from the bully pulpit. And as we have seen, his playing with fire leads, occasionally, to fatal flames.

How can the Trumpist right not see, or admit, this?

I’ve used the word “delusion” advisedly. As psychologists and scholars of religion have understood for decades, human beings will do just about anything to get rid of cognitive dissonance. If the UFO doesn’t come to take us away, we’ll invent a new myth that it’s our fault it didn’t. If a terrorist cites chapter and verse of our beloved president’s ideology, we’ll say he was attacking “religiosity” or was just a lunatic. Anything rather than admit that we were wrong. It’s human nature.

And then there’s the confirmation bias that comes from watching Fox News and living in a right-wing social media hive-mind. As soon as this attack happened, these and other sources offered ready explanations to do away with anyone’s concern that their own ideas might need some review. It’s not just me, Trump supporters could say, Fox & Friends feels the same way.

Finally, there’s ethnocentrism, nationalism, and racism, all ideologies that operate in the reptilian brain, well beneath our conscious, reasoning minds. Populist politics is primal: it goes right to core animal fears about self-preservation (“they are coming to annihilate us”), family, and safety. In Israel, this manifests as insane delusions that the entire world is against Israel, that Palestinian nationalism is simply Jew-hatred, that Arabs don’t love their children the way that we do, and that a few thousand African refugees are going to destroy the Jewish character of the state. In America, it manifests as “make America great again,” birtherism, hysteria over immigration, and anxiety about one’s own status in society.

While liberals, conservatives, moderates, and independents still talk rationally with one another, and once in a while even change sides, there’s really no reasoning with a Trumpist or Israeli right-wing nationalist. They seem deluded because they are literally deluded, because the “reasons” for their views are profoundly non-rational, even invisible.

The only question is whether there will be enough sane people, of all political and religious affiliations, to defeat them.