I saw something on Twitter the other day that said if you’re an American, you are descended from Native Americans, slaves, refugees, or immigrants. It’s true.  Even Donald Trump, anti-immigrant-in-chief, is descended from German and Scottish stock.

This article first appeared in Salon.

So what explains Trump’s anti-immigrant fervor and  the anti-immigration mania Trump has been able to tap into since the day he descended the escalator in Trump Tower and began his campaign with lies about Mexican immigrants being rapists and drug dealers?

We learned recently that the whole idea of building a wall along the border with Mexico was a Roger Stone gimmick. Once Stone saw how Trump’s anti-immigration message was resonating with potential voters, he came up with the idea of a wall along the Mexican border as mnemonic device to keep him on-message with immigration as a primary issue in his campaign.

It worked. He’s still at it. In fact, he shut down a significant portion of the government not as a way to actually get the money to build his wall, but to keep his base satiated. Trump is looking down the dark tunnel of the next two years and all he can see are the dual headlights of Mueller and a Democratic House of Representatives coming straight at him. He’s desperately afraid that if he loses his base of support among Republican voters, he’ll lose the presidency either to the legal jeopardy he faces with Mueller, or the political jeopardy he faces with a congress exercising its power to impeach him.

He is betting his presidency on the wall. Not on the actual physical wall, but the rhetorical barrier of the wall. He sees the wall as the only thing standing between him and the street, and he’s going to do everything in his power to keep it there. Trump didn’t bang his fists on the table and storm out of his so-called “negotiating session” with congressional leaders this week because Nancy Pelosi said “no” to funding his wall. He stormed out to prove to his base of supporters that he is as anti-immigrant as they are, that he doesn’t just want to stop illegal immigration, he wants to stop legal immigration as well.

The futility of it all is remarkable. People have always wanted to emigrate from one place to another. If they hadn’t, the United States of America wouldn’t exist. We began as a nation of immigrants, and we’re still a nation of immigrants, if only because we have to be. The Wall Street Journal reported this week that the birthrate in this country is at a 30 year low.

“The number of babies born in 2017, around 3.85 million, was the lowest since 1987, the Journal reported. “In order for the country’s population to essentially replace itself, researchers say that 2,100 babies should be born for every 1,000 women. In 2017, the total fertility rate—an estimate of the total number of children a woman will eventually have in her lifetime — was 1,765 births per 1,000 women, well below what is known as the replacement level.” Only two states, South Dakota and Utah, had birthrates that reached the “replacement level,” according to the Journal. Put another way, in order for the United States to maintain its population at current levels, the birth rate should be 2.1. Instead, it’s less than 1.8.

A recent report from the World Bank based on United Nations data shows a steeply declining birthrate in the United States since 1960. In 1960, the birthrate in this country was 3.7, rising from 3.3 in the mid-50’s. In 2016, the last year covered in the World Bank report, the U.S. birthrate was 1.8.

Meanwhile, our population grew from about 180 million in 1960 to an estimated 328 million in 2018. With the birth rate dropping so steeply during those decades, how did our population come close to doubling?

Well, the birthrate wasn’t always below so-called “replacement level.” It fell between 1970 and 1989, and stayed slightly above replacement level until 2009, when it fell over the next ten years to the current level of about 1.8.

So what accounts for our rise in population during a nearly 60 year stretch when the birth rate fell below replacement levels for thirty of those years? In a word, immigration.

We owe not only our population growth to immigrants, but the growth in our prosperity as well. Per capita gross domestic product measured in current U.S. dollars has grown from $3007.00 in 1960 to $59,531.00 in 2017, according to the World Bank. Not all of that growth is attributable to immigration, of course, but if you simply go by our declining birthrate in comparison to our population growth, a significant portion of our prosperity has been produced by people not born in this country. If you have any questions about whether or not this is true, look no further than California. It’s the first state in the nation with a majority-minority population, and this year its economy became the fifth largest in the world.

So why has Trump been able to tap into so much fear of immigration? In part because it’s always been there. There has been opposition to immigration by Italians, Irish, and Jews, not to mention the anti-immigration panics against Asian people and others at the beginning of the 20th Century. The “Emergency Quota Act” was passed in 1921, limiting immigration by nationality based on the population in the 1910 census. Immigration was nearly shut down entirely during the Great Depression, going from a total of 236,000 immigrants in 1929 to 23,000 in 1933, averaging only 53,000 in the decade between 1930 and 1940. Somewhere between 500,000 and two million Mexicans were deported between 1929 and 1936 in what became known as the “Mexican Repatriation.” As many as 60 percent of those deported were American citizens by birthright.

But the current anti-immigrant panic Trump has exploited cannot be attributed to the kinds of forces that drove opposition to immigration in the past. Then what is it? Some of it is outright racism, of course. The recent boomlet being enjoyed by Iowa Congressman Steve King is a reminder that racism and nativism didn’t originate with Donald Trump. The New York Times reported yesterday that King was quoted recently proudly thumping his anti-immigrant bonafides: “White nationalist, white supremacist, Western civilization — how did that language become offensive?” King asked in an interview. “Why did I sit in classes teaching me about the merits of our history and our civilization?”

King was also quoted in an August interview with a far-right publication in Austria railing against what he called “the Great Replacement.” According to the Times, King’s reference was to “a conspiracy theory on the far right that claims shadowy elites are working behind the scenes to reduce white populations to minorities in their own countries.” White supremacists who marched on Charlottesville in 2017 were caught chanting “you will not replace us, Jews will not replace us.”

But while the racism endemic to Trump’s anti-immigrant support captures the headlines, something far simpler accounts for most of it. In a word, it’s classic NIMBY. Not in my backyard has traditionally referred to changes brought on by building and expansion. Don’t build that freeway in my backyard! Don’t put in that huge new development in my backyard! But it’s also referred to people. Don’t move those black people into my neighborhood!

Trump has been able to harness the not-in-my-backyard sentiment and apply it to immigrants with scare stories and lies. Illegal immigration is down steeply, as measured by apprehensions at the southern border. There were 1.6 million arrests of illegal immigrants in 2000, and only 400,000 last year, a drop of more than 76 percent. But listening to Trump’s speech from the Oval Office this week, you’d think it was the other way around. To combat statistics that show illegal immigrants commit far fewer crimes than do American citizens, Trump substitutes scare stories about rapes and murders committed by those here illegally.

Not mentioned by Trump in his recitation of crimes was the murder of 58 and wounding of another 422 by an American citizen in Las Vegas in October of 2017 only eight months after he became president, or any of the other mass murders carried out by citizens recently. Inconvenient, aren’t they? Jeez, if only some brown guy would cross the border and pick up an AR-15 and gun down a bunch of people worshiping in a Texas church, huh? Unfortunately, Trump wasn’t able to cite any mass murders carried out by illegal immigrants, because there haven’t been any.

That’s the thing about the lies and exaggerations of Trump about immigration. They’re doomed to fail. All of those jobs taken away from American workers by immigrants? How many citizens do you see clamoring to work in the chicken plants and slaughterhouses in the Midwest and south where immigrants don the white overalls and coats and get covered in blood every day? How about those roofing jobs in the August heat in construction sites all over the country? Seen any young white guys up there pounding nails recently? I didn’t think so.

Statistically, Trump’s vaunted “base” is older and whiter than the population at large. They’re frightened of immigrants because . . . uh . . . well…er . . . uh. Rapists and murderers! That’s the ticket!

Well, I’ve got a question for my fellow aging white people. With our birth rate at a 30 year low, who’s going to pick up the slack paying into the Social Security and Medicare trust funds we are all taking advantage of now that we’ve become senior citizens?

And I’ve got a question for all of those people down in the south and in the Midwest living in towns with disappearing populations and closed schools and shuttered churches. Who do you think is going to move into those moribund split-levels and closed storefronts and do the jobs no one else wants to do and help bring those towns back to life?

It’s already happening. Immigrants are helping to pay the Social Security and Medicare bills. Immigrants are helping to revitalize dying small towns. Immigrants are filling the pews in failing churches. Immigrants are helping build the economy. Immigrants will indeed replace us, because we are not adequately replacing ourselves.

There is no wall that can be built tall enough or long enough to stop them. Just watch. Immigrants will still be entering this country on the day Trump is exiting the White House.