I used to think that Donald Trump was trying to take us back only 150 years, to the days of the Know-Nothing Party, a famously xenophobic group that insisted on the election of native-born Protestants to all offices, inveighed against “papism” and generally panicked at the thought of immigrants.

But the Know-Nothings wanted only to delay the period of naturalization of the immigrants whose religion filled them with dread and terror. They did not seek to ban their coming. Trump wants to bar Muslims from immigrating altogether. Actually. He said so in a statement Monday.

When a party called the Know-Nothings that Abraham Lincoln made fun of before the Civil War was less xenophobic than you are on Dec. 7, 2015 — something is dead wrong.

I miss those good old days when, if you wanted to say something horribly xenophobic or Islamophobic or otherwise phobic, you had to use a dog whistle. You had to be a little ambiguous about it, because we would step up and denounce you. Hate was not who we were. You could not just outright issue a statement about “preventing Muslim immigration” or state that, coming into the country from Mexico, “We have drug dealers coming across, we have rapists, we have killers, we have murderers.” You had to use weird, ambiguous imagery. (“There is a scorpion in the desert,” say.) What desert? What scorpion?

No longer.

Here’s Donald Trump’s “Statement on Preventing Muslim Immigration“:

“Donald J. Trump is calling for a total and complete shutdown of Muslims entering the United States until our country’s representatives can figure out what is going on.”

This is a promising start to a press release. Even if his premise were not hateful, wrong and flawed in every way, “until our country’s representatives can figure out what is going on” is meaningless. When, historically, have our country’s representatives EVER been able to figure out what was going on? We will wait forever.

“According to Pew Research, among others, there is great hatred towards Americans by large segments of the Muslim population. Most recently, a poll from the Center for Security Policy released data showing “25% of those polled agreed that violence against Americans here in the United States is justified as a part of the global jihad” and 51% of those polled, “agreed that Muslims in America should have the choice of being governed according to Shariah.” Shariah authorizes such atrocities as murder against non-believers who won’t convert, beheadings and more unthinkable acts that pose great harm to Americans, especially women.”

How nice of Trump to suddenly express concern for women, a demographic that has not troubled him much before.

“Mr. Trump stated, ‘Without looking at the various polling data, it is obvious to anybody the hatred is beyond comprehension.’ “

Ah, the classic Trump approach. “YOU DON’T NEED DATA FOR THIS, JUST THE VAGUE FEELING OF INCOMPREHENSIBLE HATRED.” A disregard for facts, coupled with incomprehensible hatred, is a Trump campaign trademark.

“Where this hatred comes from and why we will have to determine. Until we are able to determine and understand this problem and the dangerous threat it poses, our country cannot be the victims of horrendous attacks by people that believe only in Jihad, and have no sense of reason or respect for human life. If I win the election for President, we are going to Make America Great Again.”

Great again. This implies that Trump’s vision of America existed at some point in the past.

But it didn’t.

When in the past was that narrow and frightened greatness that Donald seeks, based on walls and religious litmus tests? 1791, when the Bill of Rights declared that “Congress shall make no law respecting an establishment of religion”? 1663, when the Rhode Island charter announced, “No person within the said Colony, at any time hereafter, shall be any wise molested, punished, disquieted, or called in question, for any differences in opinion, in matters of religion, who does not actually disturb the peace of our said Colony ; but that all and every person and persons may, from time to time, and at all times hereafter, freely and fully have and enjoy his own and their judgments and consciences, in matters of religious concernments, throughout the tract of land heretofore mentioned, they behaving themselves peaceably and quietly and not using this liberty to licentiousness and profaneness, nor to the civil injury or outward disturbance of others”?

Hardly. Trump’s America is a fantasy world. It’s like a more racist Oz, where the giant head gesticulating in front of the curtain is the Trump-Wizard’s only true form.

And he has, clearly, an active imagination. He dreamed up a fierce Civil War battle and a “River of Blood” and even put a commemorative plaque on the spot where this great big nothing happened.

He dreamed up a rally in New Jersey where thousands of Muslims celebrated on 9/11.

He dreamed up 250,000 Syrian refugees streaming into the country.

He dreamed up “rapists” and “murderers” flocking from Mexico.

He sees all of these things, vividly, in his mind, and he tells us about them using words that present no difficulty to midlevel readers. He won’t apologize. He won’t walk them back. To him, these things exist; they are as real as you or I.

The rules of Trump-world are simple: All that has to happen, for a thing to exist, is for Donald Trump to say that it exists. He is a demiurge willing people, worlds and events into being. The Word of Trump says it happened. What more do you need? He does not need to apologize. Here are some statistics that must be credible because Donald Trump believed them.

I am not usually one to object to living in the fantasy realms created by other people’s imaginations. I own too many lightsabers for that objection to carry much weight.

But Trump’s world is not a place anyone should want to live. And his fantastic vision has nasty, real-world consequences, from the Black Lives Matter protester roughed up (deservedly, said Trump) at a Trump rally, to the Islamophobes emboldened by his visions of religious registries and immigration bans. This fantasy world is spilling over into our reality and it is ugly.

This latest announcement is the icing on the Islamophobic cake. (That sounds like a horrible cake.)

But Donald Trump saying that a thing is so is — fortunately — not yet enough to make it so.

This will not make America great again for the simple reason that what he imagines is not America. This is not who we are. The world he imagines is not a place we should want to live.

If this is a cynical calculation to gin up higher poll numbers, I hope it fails. If you believe in the vision of the Founders, in the ideals of this country, or in, a word, in any of the things that have made America great so far, Trump is not your man. Do not indulge this man’s nightmarish fantasies an inch further.

The only time in America’s past that matches Trump’s exclusionary vision is when it was an icy tundra inhospitable to any life.

But maybe that’s what he’s going for.