Recently a clutch of American relatives came to visit me in London. I don’t get to see my extended family so much these days, but thanks to the internet they see me all the time, reading my articles and sending messages so supportive they occasionally reject English as insufficiently adoring and opt for Yiddish (“I’m kvelling!”). They ask me about the different things I’ve been writing about: celebrities, feminism, and so on. But when they made the transatlantic trip this time there was a rare consensus: they all wanted to talk about the rise of antisemitism in Europe.

“What is going on? It’s just crazy!” one uncle said to me after I wrote about protesting against antisemitism in British politics. We discussed the rise in verbal and physical attacks on Jews in the UK, the election of Viktor Orbán in Hungary, the Law and Justice party in Poland. He was especially horrified by the murder of 85-year-old Holocaust survivor Mireille Knoll in Paris. “It is just unimaginable,” my cousin said.

Jewish-American identity seems like it should be a pretty straightforward thing – after all, where is it easier and safer to be Jewish than in the US? I grew up in New York City, where bagels are as much of a staple as sliced bread. Not for nothing did Jesse Jackson refer to the city as “Hymietown”, for which he later apologised, and it’s a testament to the rarity of such nakedly antisemitic remarks during my childhood that I still remember that one, said in 1984. But even when we’d visit my mother’s hometown of Cincinnati, Ohio, we could still buy dreidels and menorah-shaped confetti at my grandmother’s local pharmacy, just next to the in-store nativity scene. It isn’t just us elite, east coast, alternative, intellectual, leftwing (“Jack, just say, Jewish, this is taking for ever,” as Liz Lemon said on 30 Rock) American Jews who take our assimilation for granted.

Some Jews of my grandparents’ and parents’ generations had their ears cocked for hints of antisemitism, but they always reminded me of Alvy Singer in Annie Hall, hearing imagined slurs in small talk (“I said, ‘Hey did you eat yet?’ and Tom said, ‘No, Jew?’ Not did you – Jew!”) I grew up in an era in which the two biggest US TV shows were Seinfeld and Friends, the former being a show about assimilated American Jewishness, that assimilated its own Jewishness so much that it looked positively mainstream. In Friends, Monica and Ross Geller’s Jewishness was treated like Chandler’s sarcasm – as a natural and endearing quirk. Any attacks on American Jews – the 1994 shooting of four Hasidic teenagers in Brooklyn, the 2009 killing of the security guard at the US Holocaust Memorial Museum – felt random and rare. Hell, this is America, where people are shot every day, and compared with other groups, Jews have been relatively little targeted. Is it any surprise many of us became complacent? The commonly understood story was that our ancestors all fled from danger to the US – a place of safety, the land of menorah-shaped confetti.

Trump has unleashed US antisemitism like the environmental protection guy in Ghostbusters releasing long-dead ghosts

The day after this week’s mass killing at Pittsburgh’s Tree of Life synagogue, the deadliest attack on Jews in the US, it already felt as if something fundamental had shifted in Jewish-American identity. All that time American Jews were being shocked by what they saw in Europe, they didn’t realise those same attitudes were fermenting at home. Jews aren’t explicitly cited as nefarious influences in the way, say, Muslims are – since 1944 obvious antisemitism is generally frowned upon. But antisemitic language – “globalists”, say, or “Soros” – has been fully normalised by rightwing US politicians and media, and Jews know from history that this kind of talk does not end well for them.

Despite all the guff about how much President Trump loves the Jews because his daughter is one (not that having a daughter has stopped him from being a revolting sexist pig), he has unleashed America’s current antisemitism, like the Environmental Protection Agency guy in Ghostbusters releasing long-dead ghosts. Throughout his presidential campaign he has played on antisemitic tropes, alluding to secretive wealth, shadowy cabals and divided loyalties. While it’s doubtful Trump even understands what he’s saying these days, he knows what gets his people cheering. What happened in Pittsburgh was not random, it was an inevitable culmination of a political direction.

Many of my British friends are becoming increasingly conscious of their Jewish identity, as opposed to their British Jewish one. Nothing lets you know you are less assimilated than you thought faster than being consistently “othered” by politicians across Europe. Some American Jews will now go through a similar process, and it will be painful, because our identity was always a statement about the values of the country that had taken in our ancestors. Those values are looking a little shaky right now. This isn’t about a lack of patriotism or split loyalties, or whatever antisemites say. It’s what happens when you never wanted to leave your home, but your home has started to leave you