This has been a very difficult 24 hours for the Jewish community — and for America. What started as a normal Sabbath for Jews — a time to be with family and community, celebrate bar and bat mitzvahs, hold baby namings, pray to God — ended with news of the massacre at the Tree of Life synagogue in Pittsburgh. This was the deadliest anti-Semitic attack in American history.

While the horror of this massacre is shocking, it is not entirely surprising.

At the Anti-Defamation League, we have been tracking and fighting anti-Semitism for over a century. And while Jews have enjoyed a degree of acceptance and achievement in the United States perhaps unrivaled in our people’s history, recent trends have been alarming.

While the overall trend in anti-Semitic incidents has been a downward one, last year we saw the largest single-year increase since the A.D.L. began this annual audit in 1979 — a 57 percent increase in anti-Semitic incidents in 2017. These incidents include high-profile ones such as neo-Nazis marching in Charlottesville, Va., chanting “Jews will not replace us,” physical assaults, vandalism and attacks on Jewish institutions.

Part of this sharp rise comes from a large increase in anti-Semitic incidents in grade schools and on college campuses, which nearly doubled for the second year in a row. The latest F.B.I. statistics corroborate what our researchers found: a 5 percent increase in reported hate crimes, with more than half of faith-based hate crimes — 53 percent — against Jews.