WASHINGTON — Perhaps it was naivete, ignorance or stupidity — or all three — but when I was growing up in the 1950s in a suburb of New York City, I had no sense of anti-Semitism. By that, I do not mean that I looked around and found little evidence of anti-Jewish feeling. I mean that I had no concept of anti-Semitism. To me, it didn’t exist. I had as much knowledge of it as I did of, say, quantum physics. Nothing at all.

There were very few other Jews in my public elementary school, and I did not feel different from the students, with Christmas as a minor exception. The singing of those Christmas carols made me uncomfortable. But there was no wrenching identity crisis. I mouthed some of the songs that seemed religious and sung those that didn’t. My family straddled the divide between the secular holiday and the religious. We had a Christmas tree and presents; but we also celebrated Hanukkah. More presents!

I saw myself then — and see myself now — as an American, whose fundamental religion is Americanism. By this, I believe that being an American is just about the greatest identity anyone can have. That’s my faith, and one of the fabulous things about being an American is that you can practice whatever your personal religion is without anyone — including the government — interfering, as long as you don’t threaten others. I am not a very good Jew; I don’t know most of the Hebrew prayers and go to synagogue mostly around the Jewish new year. To boot: I am an agnostic. Still, I wouldn’t surrender my Judaism for anything.

Of course, I know a lot more about America now than I did as a third-grader, and much of what I have learned in more than 60 years does not reflect well on us as a society. Conflict was a large part of our heritage. I learned that the Civil War failed to solve all the injustices of race, many of which linger to this day. I learned that many of the great advances of the U.S. economy were often accompanied by hardships and suffering that, in some cases, were inexcusable and, in others, were simply cruel.

And, naturally, I also learned that the relationship between Jews and America was a lot more complicated than I had imagined. In the real world, anti-Semitism was widespread. Covenants prevented Jews from living in certain neighborhoods; many companies wouldn’t hire Jews; clubs wouldn’t accept them as members. But I also thought that, after World War II, many of these abhorrent practices had been outlawed or had receded before new norms of public opinion. Most Jews had assimilated into the mainstream of American life.

I had assumed that my three children, now in their late 20s and early 30s, would grow up in a world where their Jewishness, depending on how much they felt it, would remain mostly a private matter. For all that I had learned, I still accepted my basic childhood perception that, in this country, Jews were Americans like anyone else, and they lived in a society that would treat them as equals, as everyone should be treated. This was one of the glorious gifts of being an American. This was my faith, and it was shared, I think, by many Jews.

We were wrong; I was wrong. Anti-Semitism had not disappeared. It had simply hibernated. The tendency to turn normal disappointments and setbacks into obsessive hatred and deranged anger has proven indestructible. It’s made worse by being promoted by national leaders who exploit it for political advantage. This creates a permissive climate for overheated rhetoric and (ultimately) violence that, in varying forms, afflicts much of our political culture. What’s missing is bipartisan self-restraint that is a sign of maturity.

The slaughter of 11 worshippers in a Pittsburgh synagogue is a great tragedy; but so were the killings of dozens of others in many different settings — schools, concerts, churches. Our descent into this societal inferno is obviously a condition that affects more than Jews.

The promise of America is that we all consider ourselves Americans first — and then whatever else we are as individuals. This defines how people engage with the larger society. But we are losing this essential cohesion and are being fragmented (“sliced and diced”) into a society of different and clashing loyalties. If Jews — as well as African-Americans, Hispanics, Muslims and even whites — are singled out as groups that need special protections or privileges, they will paradoxically become second-class citizens, deprived of the full freedoms that are central to our character and dependent on the goodwill of the larger majority. That is what’s at stake.

Robert Samuelson is a columnist with The Washington Post.