The story of America is the story of immigrants. Almost every one of us can trace our bloodlines back to a people who arrived on these shores from other soils.

The tapestry of our nation was woven by the toils of newcomers and dyed by the blood of forced labor. All of us are byproducts of a hope that past generations had for their children. Apple pie and baseball take back seats to the narratives of foreigners who made a new home here—there is nothing more American than immigrants.

Therefore, when Donald Trump takes to the podium to demonize immigrants and spew xenophobia into the public square, he is spitting on the foundation of our nation. A man who got elected president promising to make America great again is vilifying the people who made America great.

There is irony to all this. Trump’s grandfather Fredrick was an immigrant who left Germany when he was just 16 years old. He boarded a steamship and arrived in New York in 1885. Fred moved in with his sister and started working as a barber the next day. After cutting hair and trimming beards for six years, he had saved enough money to move to the West Coast and open a restaurant.

If this story sounds familiar, that is because Fred’s journey is the typical immigrant story. Donald Trump was bestowed fortunes from his father only because his immigrant father once tasted the life of a migrant worker in New York. Of course, Donald knows this all too well; his mean-spirited attacks on Mexicans and Muslims is nothing more than a malicious ploy to cater to the bigotry of some of his most spiteful loyalists.

One can understand zealots who are driven to hatred out of brokenness. What is harder to forgive is Trump’s calculated dog whistling as he smears immigrants as exotic outsiders who don’t belong here. A reality show jester who thinks every occasion is a deal waiting to be leveraged, he intentionally blows fire on the political and social discourse in order to keep his name on our lips.

He changes positions on a whim in order to maximize his ratings. When he was in blue New York, Trump was a liberal’s liberal. Now that his fortunes depend on sectarian Kool-Aid drinkers on the right, he pivoted on a dime as he transformed from Jimmy Carter lite to uber-Strom Thurmond overnight. Comparing Trump’s videos from 2008 and now will give your jawbones a workout, your mouth gaping as you hear him praising Hillary Clinton a decade ago and now portraying her as Medusa.

Putting aside Trump’s duplicity, it is incumbent on Americans to be united in our rebuke of his hostility toward immigrants. Patriotism is not sloganeering. You can’t make America great again by maligning the people who made it so. The pilgrims who landed at Plymouth Rock were undocumented migrants who survived thanks to the grace of Native Americans. Our nation was enriched thanks to the blood and sacrifice of millions of coerced migrants from Africa. America was connected thanks to the toil of Chinese railroad workers. Great cities like New York, Chicago and others owe their existence to the labor of European immigrants.

Our nation is a testament to the immigrant experience. While I understand the need for an immigration framework, we can arrive at a solution of a fair and equitable immigration system without marginalizing people who come to America with hope for a new future as Donald Trump’s grandfather once did.

These issues are personal for me. I arrived in America as a 7-year-old after my family fled my homeland of Ethiopia to escape the Red Terror in the late 1970s that took the lives of at least 200,000 Ethiopians. We came here with few possessions. My dad worked three jobs concurrently to pay the bills and keep a roof over our heads. He died of lung cancer in 2001, and I am sure the strain he put on his body through the years played a large part in his eventual death.

When Donald Trump insults immigrants and impishly disparages people who seek refuge in America, he’s really insulting my father and besmirching the memory of his own grandfather. Beyond that, defaming immigrants is a direct attack on all of us. When political leaders start otherizing and turning people into abstractions, what starts as an attack against a few eventually becomes an inferno that engulfs many.

We would do well to remember the story of Germany in the 1920s and ’30s. First, they came for the undesirables. Then, calamity came for all.