The massacre of eleven Jews at Etz Chaim (Tree of Life) Synagogue in Pittsburgh by white-supremacist Robert Bowers last Saturday sent shock waves through the American public, the American Jewish community, and the Left. In the wake of the deadliest antisemitic terror attack in US history, vigils have been organized across the country, support has poured into the reeling Jewish communities of Pittsburgh, and progressives are grappling anew with the question of antisemitism.

Even before the Pittsburgh massacre, antisemitism was on the rise, with the startling wave of far-right, ultranationalist movements across Europe and the US. In America, alt-right antisemitism burst into public view with social media attacks on Jewish journalists and institutions during the 2016 elections, and took to the streets with tiki torches and chants of chants of “Jews will not replace us” in 2017. Across Europe, the United States, and Israel, ultranationalist leaders and political parties demonized billionaire Hungarian Jewish philanthropist and Holocaust survivor George Soros with frightening vitriol, scapegoating him as the supposed mastermind behind migration, refugee resettlement, and other humanitarian causes.

But even as its power grows, far-right antisemitism remains a poorly understood phenomenon for much of the Left. How are we on the Left to understand antisemitism? Why is it rebounding, with renewed vigor, in the era of Trump? And most importantly, how do we fight back?