When Donald Trump declared his candidacy for president at Trump Tower on June 16, the real kickoff wasn't the actual announcement ("I am officially running") but his remarks on immigration. "The U.S. has become a dumping ground for everybody else's problems," he said, and then went on to denounce Mexican immigrants as criminals, drug dealers, and rapists. "We have no protection and we have no competence, we don't know what's happening. And it's got to stop and it's got to stop fast."

Fact checkers squawked. They pointed out that net immigration from Mexico is now zero, if not negative (that is, the number of people returning to Mexico from the U.S. is at least as great as the number of new arrivals), and that there are now more arrivals from Asia than from Latin America.

When questioned, Trump refused to back down. Instead he accelerated, pointing to a handful of criminal acts by undocumented immigrants as a virtual crime wave. Trump has since widened his scope of attack on immigrants by saying on Face The Nation that Syrian refugees may be "the greatest Trojan horse" — that is, there may be terrorists among them — and should be steered away from American shores.

But fact checkers aren't Trump's intended audience. He's targeting the mass of disaffected, angry, and largely white voters who feel that immigrants have stolen their jobs, their sense of security, and their self-respect. These voters are looking for someone to get things back on track, to bring back "their" America — and poll after poll shows that they like the Knight on a White Horse message Trump is delivering.

Trump's anti-immigrant rant and follow-up pledge to deport all undocumented immigrants and their families have proved a shrewd campaign tactic. But as I learned while writing a book about him, his father, and his grandfather, despite Trump's repeated claim to "tell it like it is," he has often failed to do so with regard to his own family's immigrant past.

Like most Americans, Donald Trump comes from immigrant stock, and as in most families, their story is a complicated one, with many chapters. But during Trump's anti-immigrant tirades, he failed to mention even such basics as the fact that his mother, Mary Anne McLeod Trump, was born in Scotland, that he is named after a Scotsman (a maternal uncle), and that he has boasted of his tie to this foreign country repeatedly when publicizing his golf courses there.

More important, his black-and-white denunciations give no hint that his financial empire traces its origins back to the shrewdness with which his grandfather, Friedrich Trump, finagled his way around the rough-and-tumble New World after emigrating from the small German village of Kallstadt. The year was 1885, and Friedrich, who was only 16 when he landed in New York City, belonged to a wave of German immigrants that, again according to the Pew Research Center, made that country the largest source of newcomers to the U.S. for more than four decades.

Being born in Germany wasn't a problem when Friedrich arrived in the United States. He went on to become an American citizen and to amass a nest egg — the first Trump family fortune — by "mining the miners" in Seattle and the Yukon during the gold-rush era. Rather than dig for ore himself, he opened restaurants, often in the red-light district, and supplied booze and easy access to women. Although such behavior does not rise to the level of the criminal activity grandson Donald claims is rampant among immigrants from Mexico, the local North West Mounted Police superintendent found it unacceptable — and in 1901, when he announced a clean-up, Friedrich pulled up stakes and headed back to New York.

That's when he hit his first major bump in the road, in the form of a dilemma that often arises in immigrant communities: Friedrich had adjusted to life in his new home, but his wife Elizabeth, also from Kallstadt, had not. Although Germans were the biggest ethnic group in the U.S. and New York City had the third-largest number of German speakers in the world, behind only Berlin and Vienna, Elizabeth was desperately homesick. Friedrich did his best to make her feel at home in the U.S., but ultimately, in 1904, he, Elizabeth, and their infant daughter headed back to Germany — what Mitt Romney would have called "voluntary self-deportation."

When Friedrich applied to regain German citizenship, he hit a second big bump: He had left his native country when too young to do military service, which was compulsory in Germany, and he was returning after he was over the age limit. He insisted that the only reason he had immigrated was to provide for his widowed mother, but the authorities dismissed him as a draft dodger. Many observers would consider such an infraction less serious than the rapes and drug-dealing Donald accuses Mexican immigrants of committing, but German officials kicked Friedrich out — ironically, the same fate Donald would like to mete out to undocumented immigrants and their families today.

In 1905, Friedrich and his family sailed back to the U.S. Despite Friedrich's best efforts, the Trump family would be Americans after all.

Friedrich died in May 1918, just before the end of World War I. There was a rising tide of anti-German sentiment in America, manifested in accusations of disloyalty against people with German backgrounds, diatribes against music by German composers, even bonfires of books by German authors. People with German names changed them, and readership plummeted for the nation's hundreds of German-language publications.

This xenophobic atmosphere had a profound impact on Friedrich's older son, Fred (named after Friedrich but in an Americanized form). Only 12 years old when his father died, Fred was now the man of the house, and he began to tamper with his family history — that is, to tell it like it wasn't. Despite growing up in a German-speaking home and speaking his parents' language on visits to Kallstadt, he said he didn't know German, and by the beginning of World War II, he said his family was from Sweden.

Elizabeth Trump, Fred's German-born mother and Friedrich's widow, lived across the street from Fred and his family. She was a regular presence in their lives and didn't die until 1966, when Fred's son Donald was 20; nonetheless Donald, too, preferred to describe his ancestry as Swedish — to tell it like it's not — and did so in his autobiography, Trump: The Art of The Deal, published in 1987.

Eventually, it became impossible to keep up the bogus Swedish origin story, and in a 1990 interview with Vanity Fair, Donald acknowledged his German heritage with a carefully parsed version of the truth ("My father was not German; my father's parents were German"). But he then distanced himself from the facts — i.e., told it like it wasn't — by adding that his grandparents had really been "from all over Europe" (they weren't) and saying that he mentioned Germany only so that all the people in Sweden who seemed to be expecting him to visit would know why he hadn't done so.

Whatever Trump's failure to "tell it like it is" about his own immigrant family, he has put in an even more dismal performance when it comes to telling it like it truly is about the history of immigration to this country, and about the way in which every successive wave of immigrants has ultimately assimilated into American society.

Thus, for example, German-Americans — the same group to which Donald himself belongs and that was so stigmatized during World War I and World War II — have become so assimilated that few Americans realize this remains America's largest national ethnic group.

The same assimilation process is happening today with other immigrant groups, as documented in a recent report from the National Academies of Sciences, Engineering, and Medicine that looked at 41 million immigrants, including 11.3 million who are undocumented. The report found that, contrary to suggestions by Trump and other anti-immigrant groups, these newcomers are not anti-social and unhealthy misfits leeching off our health-care and educational systems. Rather, they are eager to learn English; have lower rates of obesity and chronic disease and fewer deaths from cancer and heart disease than native-born Americans; and have much lower rates of crime and violence in the cities and neighborhoods where they live than similar locations lacking immigrants.

Zeroing in more specifically on Mexican immigrants, a study published in 2015 by the American Immigration Council found that the incarceration rate for less-educated young native-born males is more than three times greater than comparable Mexican immigrant young males.

Given his own family history, one might expect Trump to endorse America's history of embracing immigrants. Instead, he declared in his announcement speech, that, next to repealing ObamaCare, the top priority in his presidency would be "to build a great, great wall on our southern border."

Arguably, the wall Trump proposed would keep Mexicans out of the U.S. But, at least in the aggregate, it might also spare Mexicans bad health, criminality, and prison — and it would certainly deprive this country of the vigor and energetic striving associated with every new immigrant group.

Whether this anti-immigrant agenda would ultimately put America back on track, and the trade-offs that would be involved, are something every candidate — indeed, every American — needs to think about.