A longtime friend of mine, someone I’ve known since high school and with whom I was more or less “best friends” for 20 or 30 years, last year terminated our friendship because I wrote that I thought Israel has a right to exist, that Palestinians have the right to a state, and that in Israel’s war with Hamas there is no moral high ground. I sent the clip of my column to Kurt (not his real name), an ardent anti-Zionist and an atheist of Jewish descent, because it dealt in what I felt was a nuanced way with a subject I thought would interest him.

He replied with a shockingly hostile letter calling me “a Zionist,” which to him is the approximate equivalent of a Nazi, and telling me as a definitive kiss-off to enjoy my old age. I had no idea my essay would provoke that kind of reaction — he called my sending it “a provocation”— and I was frankly stunned and saddened to realize how full of hate he was. Over the years we’d had our disagreements, our ups and downs, our natural drifts apart and reconnections, but this felt final.

Kurt has always been more political than me — he studied political science at UC Berkeley, participated in the Free Speech Movement, went to law school there and became, for a while, a criminal defense attorney in San Francisco. A man of the intellectual far left, more theoretical macro-analyst than on-the-ground activist, he presented himself as “anti-political,” a philosophical anarchist who didn’t reflexively support leftist or progressive causes. I consider myself an independent-minded liberal Democrat, but I never asked him whether or not he voted.

In the 1980s, when I was engaged in cultural solidarity work with the young Sandinista government in Nicaragua during Ronald Reagan’s Contra war, Kurt was skeptical of the Sandinistas’ anarcho-democratic credentials. He was anti-authoritarian, whether from the right or the left, even though at the time the Sandinista leadership was a loosely organized collective that had chosen Daniel Ortega as their presidential candidate because he was the best-looking and most innocuously uncharismatic among them.

Anyway, Kurt’s anti-Zionism ran deep, based on the historical injustice of displacement of Palestinians from their ancestral lands and the religious myth of Jews’ biblical right to “return” there. I have resisted using the word “genocide” to describe Israel’s current mass murder of Palestinians, but now that the whole population has been starved by Israel’s blockade of aid, I don’t know what else to call it. The point is that, like many anti-Zionist ideologues, my old friend Kurt is righteously opposed to all things Israeli, and the horrors of Israel’s outrageously disproportionate assault on Gaza and its people has naturally further inflamed his antipathy.

Apocalyptic political events can drive people apart. I’ve seen marriages broken up by the Sept. 11, 2001, attacks on the United States, with husbands stoked for violent revenge in a way that spooked their spouses and fractured their partnerships beyond repair. Some Jewish friends of mine and I may disagree about Israel’s terrible choices in response to the Hamas atrocities of Oct. 7, 2023, but we don’t discuss the topic and we accept our differences of judgment. Kurt could extend no such tolerance to me.

A year after his letter firing me as his friend, it looks to me like maybe our friendship was ending anyway. Since quitting the courtroom he had become an accomplished novelist whose two most recent books I couldn’t finish because I don’t have the time or patience anymore for those kinds of lengthy narratives — my own limitation as a reader, no reflection on the quality of his storytelling. But I expect this difference in our literary capacities contributed to his bitterness over my acceptance of Israel’s existence despite its tragic origins and current crimes. It was and is the vehemence and aggression of his rejection that gets to me, though I know now how poisonous ideological hatred can be.

Stephen Kessler’s column appears on Saturdays.