Throughout history, Jews have been killed simply for being Jews.

Jews have been killed in communal areas. Jews have been killed inside Jewish buildings. Jews have been killed in the street. Jews have been killed in their homes. And Jews have been killed in concentration camps. We have been killed wherever we are and wherever there are Jew haters.

But the murder on Saturday of eleven congregants at the Tree of Life synagogue in Pittsburgh is so shockingly and startlingly poignant because it was in a shul, on Shabbat - at the very time when we gather together in our various communities.

In the days since the killings, perhaps the most common reaction has been — beyond the heartfelt thoughts and prayers for those directly affected — the realisation that what happened in the Tree of Life shul is the nightmare that each of has whenever we gather together. It is the nightmare come true. We are not scared and we will never be cowed.

But we do worry — we worry when we drop off our kids at Jewish school or cheder, or when we arrive at shul, that this will be the day when history repeats itself. Last Shabbat, in Squirrel Hill, it did. 

It is important to be clear that the only person responsible for the murders is the man who pulled the trigger. But it is also important to understand that there is a climate and a context for everything. There is a time when hatred festers and is fed and a time when it does not.

Robert Bowers was not a supporter of President Trump. His social media posts show that he was angry that Mr Trump was too friendly with Jews. And it is literally true that some of Donald Trump’s best friends (including his daughter) are Jewish.

But it is also true that President Trump has fed the hatred that is now the undercurrent of US politics. Specifically, he has fed the hatred of Jews. His 2016 campaign was full of sly references to Jews that would be discernible as such to Jew haters everywhere, and even created an ad attacking “global special interests”  and people “that don’t have your good in mind” — every one of whom was Jewish. After Charlottesville, President Trump said there were “very fine people” marching among the neo-Nazis chanting “Jews will not replace us”.

Mr Trump is, consciously, feeding an atmosphere in which hate thrives. He is using hate as a political tool.

To repeat: President Trump was not responsible for the murders in Pittsburgh. But he gives licence to antisemites — and this is the climate in which men such as Robert Bowers read, watch and then sometimes act.

But while this is clearly an American issue — along with the ready availability of the guns that make such murders possible — there are Jew haters here in Britain, too, who speak the same language of death and murder. British Neo-Nazis have been convicted of serious plots to kill those they hate. Jewish public figures are targets for hate.

That is just one reason why the murders in Pittsburgh strike so close to home.

But more than anything else, it is because we all share the grief and the horror and we all feel the pain. We read the stories of the eleven men and women killed. And we mourn their deaths.