She never wanted to come to America. She only did it to make money, enough money to bring over her five brothers and sisters. She waited 16 years before bothering to become a citizen, and took the step mostly to avoid being deported. She never learned more than a few words of English, not even after decades in her ambivalently adopted land. She shopped in stores where she could use her native tongue, and she read newspapers that were written in it, and she attended plays whose actors spoke it. If something needed to be done in English, she left the transaction to her children. Most of what the kids cared about, the movies and sports and foods, was only fit for "American dopes," as she put it in one of her favorite phrases. Everything was better back in her home country. The bread was better, the clergy was better, the holidays were better. He lied his way into America. He hid any record of his prison sentence and his jailbreak. He snuck past the border guards by carrying a stolen passport and using a false name. After just a few years in the United States, he was in jail again, suspected of being part of a terrorist gang. He never married his female companion, just shacked up and had children. He sired four of them, and for a while he did not even enroll them in public school. The eldest, a daughter, took up at 18 with a boyfriend, and naturally they, too, had a son out of wedlock. WE ALL know, we Americans in the midst of a vitriolic national debate about immigration, just how abominably newcomers to our country behave - the way they take jobs from our own people, the way they refuse to assimilate, the way they flout our moral values and our criminal laws. I certainly know, because the two undesirable immigrants I've described to you happen to be my grandparents. My maternal grandmother, Rose Markiewicz Hatkin, reached Ellis Island from Bialystok, Poland, in 1920. My paternal grandfather and namesake, Samuel Freedman, landed in New York in 1912, having stopped for several years in the Jewish slum of London's East End on his escape from Czarist Poland. He was a menace to society, my grandfather, sentenced to death at age 14 for his role in garment workers' strike. He was Reichgold until the 1905 uprising that liberated his prison, and somehow in flight he obtained the passport for Freedman. By the time he made it to America, he had studied and adopted anarchism, and his organizing efforts in a New York factory put him behind bars there, until receiving a Christmas clemency from Al Smith, a governor sympathetic to unions and immigrants alike. True to the anarchist faithlessness in government, he refused to legally wed my maternal grandmother, and put his children until their teenaged years into an experimental school that was the central institution of an anarchist colony in rural New Jersey. My aunt Clara, their eldest child, saw no reason to marry my uncle Sid, whom she'd met when he was the drummer in an all-anarchist jazz band, until decades after they had formed a couple, and even then only as a concession to inheritance laws. As for my maternal grandmother Rose, I cannot claim any high idealism for her half-hearted acceptance of America. She simply was one of those immigrants who never especially wanted to be here and who endured for purely utilitarian reasons - initially the chance to get her siblings out of endangered Poland, then the opportunity to have her two daughters receive a full education and prospects for advancement that offered. Her own life in the East Bronx proceeded within a Yiddish-language universe of the Forverts, the McKinley Square Theater, and the Jennings Street pushcart market. Up to her dying days in the 1970s, she could only understand and be understood in Yiddish, preferably at an ear-splitting volume, because in some strange act of principle, she resisted wearing her hearing aid. SO, YOU see, all of the calumnies being heaped on today's immigrants from Mexico, the Dominican Republic, China, and other foreign countries have been heard before. They are the same ones leveled at our own Jewish ancestors, as well as Catholics from Ireland and Italy. They contributed to the closing of America's Golden Door in the immigration-restriction legislation of 1924, exactly the sort of punitive statute today's nativists would wish to enact as a response to the liberal immigration law in effect since 1965. Articles about "the Jewish problem," a staple of new York journalism in the early decades of the 20th century, identified Eastern European immigrants as "ignorant," "primitive," and "the dregs of society." The novelist Henry James wrote of the Lower East Side in The American Scene: "It was like being at the bottom of some vast aquarium surrounded by innumerable fish with overdeveloped proboscis bumping togetherâ€¦Here was multiplication with a vengeance." When William Jennings Bryan was locked in battle with Al Smith for the Democratic presidential nomination in 1924, he declared of Smith's immigrant supporters, "You are not the future of this country." As the two houses of Congress have passed drastically different bills - the House of Representatives' measure emphasizing punishment, arrest, and deportation; the Senate's providing a route to citizenship for 12 million illegal immigrants already in the country - the debate has danced around the real, underlying issue. The public discussion has turned on whether immigrants do or don't take jobs from and drive down wages for American citizens, whether the existing security along the border can protect the country from terrorists trying to infiltrate. Barely beneath the respectable public rhetoric simmers the actual grievance, the emotional trigger for this surpassingly ugly moment. It is the presumption on the part of immigration opponents - the fevered fear - that the most recent arrivals have neither the will nor the skill to Americanize. It is the passionate delusion that all these Hispanics and Asians and Africans will dilute the national character, as if such a thing were ever fixed in the first place. My derelict grandparents somehow managed to raise children who earned college degrees, held professions, and mastered the classical music and drama of the Western world. I don't think my family's story is an unusual one, either. It is the story of the Jewish encounter with America and the American encounter with Jews. Now when the hounds of bigotry are baying, when too many Americans have forgotten their forebears' time as strangers in a strange land, we must make the protection of today's immigrants one of our signature communal priorities. This obligation is only what we owe to our ancestors. The writer, whose column usually appears biweekly on Wednesdays, is a professor of journalism at Columbia University and the author most recently of Letters to a Young Journalist. Saul Singer is on vacation.