During the run-up to America’s war against Iraq, I told audiences that Bush would certainly win reelection. Some people broke down in tears.

That’s my job: telling people things they prefer not to hear, especially about the future. Being Cassandra isn’t much fun. Because we live in a nation in decline and yielding to incipient fascism, the more I’m right — i.e., most of the time — the more I annoy my readers.

So please believe me when I say this gives me no pleasure: Donald Trump isn’t bluffing when he threatens to deport the estimated 11 million people living in the U.S. illegally.

Are you undocumented? Prepare to go underground.

Are your papers in good standing? Are you a good person? Prepare a hiding place in your home.

Dark days are ahead.

Do not take comfort in the fact that Trump flip-flops on all sorts of issues. Contrary to his initial, typically strident position on abortion, the master demagogue now says women needn’t fear imprisonment if they terminate their pregnancy (unless he changes his mind again). Even his much-ballyhooed Great Wall of Trump along the Mexican border may wind up as half a wall. He does this a lot.

But there’s no way he’ll back away from mass deportations.

Why are deportations different? Radical nativism, as defined by this promise to deport illegal immigrants, every single one of them, defined his campaign from the start. It’s why he’s here. It’s why he won.

Reneging on deportations would be like Bernie Sanders asking Goldman Sachs for donations or Hillary Clinton changing her gender — it would betray the raison d’être of his campaign. He can’t back down without losing most of his support.

The optics of the biggest forced population movement since those carried out by Hitler and Stalin would be awful. Police kicking down doors. Women and children dragged off in the middle of the night. Neighbors, friends, colleagues, lovers, spouses — disappeared.

Countries of origin would be reluctant to absorb millions of new arrivals, all unemployed, many of them who came to the U.S. as children and thus have no memory of their “home” countries. So the Trump Administration would have to build concentration camps to house them.

Because the idea is so outlandish, so fundamentally un-American, it’s too much to contemplate seriously, even for journalists. They’re in denial. If Trump wins, however — and it’s entirely possible he will — he will carry out his plan.

Legally, there’s nothing to it. Trump doesn’t need an act of Congress. He doesn’t even have to sign an executive order. All he’ll have to do to set this outrage in motion is pick up the phone and tell the head of Immigrations and Customs Enforcement to do his or her job: enforce the law.

Camps cost money. So do more agents. No problem. President Trump can shift his budget priorities in favor of ICE. He’s already said he would triple ICE’s enforcement division from 5,000 to 15,000 officers. The FBI would have to pitch in.

Backlogs in the nation’s 57 existing immigration courts run as long as two years. The system would have to be expanded.

I look to Trump’s authoritarian impulse to turn initially to the federal budget. I imagine him making a pitch that goes like this: “I won because the American people wanted my business acumen in charge of government. Congress has totally messed up the budget process with their budget stand-offs. Let me take care of the budget, and I promise you an end to this crap. Take your kids to a national park and I guarantee it won’t be closed due to some government shutdown, believe me.” Compliant media + perceived mandate + popular exhaustion = Trump gets his way.

Sad but true: subtracting 11 million people from the population, and thus two to four million from the workforce, will put money into the pockets of everybody else. Fewer workers means labor has more clout. Wages will go up.

Meanwhile, deportations will empty housing stock. Rents will decline.

In the short term, anyway, Trumpism could stimulate the economy. That would be popular.

Establishmentarians can’t imagine that Trump would actually go through with mass deportations, much less how he would carry them out. “I can’t even begin to picture how we would deport 11 million people in a few years when we don’t have a police state, where the police can’t break down your door at will and take you away without a warrant,” says Michael Chertoff, head of the Department of Homeland Security under George W. Bush.

You don’t need imagination to game this out. You need history.

Right-wingers will call the cops to report their undocumented neighbors. As in Nazi-occupied Europe, anyone with a grudge against someone without a valid I-9 form — resentful ex-boyfriends, etc. — will drop a dime to Trump’s jackbooted thugs. Checkpoints will spring up on roads, at bus stops, in train stations. Not that they have to; mass surveillance by the NSA ensures that the feds already know where illegals live.

It won’t be hard to find judges to issue warrants based on those reports.

For Trump, deportations are a political necessity he can easily execute. For his critics, they won’t occur because they would run against our societal values. “Unless you suspend the Constitution and instruct the police to behave as if we live in North Korea,” Chertoff says, “it ain’t happening.”

More than most people, Chertoff ought to know better. After all, he served under a radical right-wing president who convinced us to go along with perpetual war, concentration camps, legalized torture, invading foreign countries for fun, killer drone planes and a new cabinet-level bureaucracy whose mission — and very name, Homeland Security — evokes Nazi Germany.

It doesn’t take much to convince Americans to accept the unacceptable.

(Ted Rall is the author of “Bernie,” a biography written with the cooperation of Democratic presidential candidate Bernie Sanders. His next book, the graphic biography Trump, comes out July 19th.)