Oct. 27 marked the one-year anniversary of the horrific shooting at the Tree of Life synagogue in Pittsburgh. A lone gunman, armed with an AR-15, entered the sanctuary shouting anti-Semitic slurs, killing 11 congregants and injuring many others. The incident marked the deadliest assault on the Jewish community in the history of America.

Unfortunately, this act did not occur in isolation. Anti-Semitism is not only alive and dangerous in the United States, but it is on the rise.

On Oct. 12, a Jewish man in the Crown Heights neighborhood of New York was slapped across the face and called “a dirty Jew” — the latest in a growing series of violent assaults targeting Jews around Brooklyn.

Also in October, anti-Semitic posters were plastered to the doors of a synagogue in Grand Rapids, Michigan, featuring the head of Hitler with the caption “Did you forget about me?” and the slogan that it’s time for a “crusade against Semite-led subhumans.” (Additionally, J. recently reported on anti-Semitic hate flyers that were posted at a Modesto church; see tinyurl.com/jweekly-modestohate.)

In a just-released survey by the American Jewish Committee, more than 80 percent of Jewish respondents say they have witnessed an increase in anti-Semitic incidents in the United States over the past five years, with 43 percent indicating that the increase has been significant.

That anti-Semitism is spiking is not only a matter of perception, however. The Anti-Defamation League reported a 150 percent increase in recorded incidents comparing 2013 with 2018.

American Jews clearly see that the hike in white supremacy goes hand in hand with the hike in anti-Semitic incidents across our country: 89 percent of AJC respondents believe the extreme political right presents a threat to Jews.

RELATED: Nearly 9 in 10 American Jews say anti-Semitism is a problem in U.S.

Donald Trump’s presidency has helped embolden white supremacy throughout America. He has routinely refused to condemn their hatred. At the same time as Trump often refuses to criticize far-right extremist groups, he himself has engaged in harmful rhetoric, claiming in August that any Jewish person who votes for a Democrat shows “either a total lack of knowledge or great disloyalty.” Throughout history, we know how deadly questions of Jewish loyalty can be.

It is no wonder that the AJC poll showed nearly three-quarters of Jewish voters disapprove of Trump’s handling of the anti-Semitism threat, with more than six in 10 showing strong disapproval. Only 22 percent of Jewish voters have a favorable opinion of Trump’s performance; 76 percent have an unfavorable opinion.

Forty-one percent of respondents to AJC’s survey believe that the Republican Party bears all or close to all responsibility for the current levels of anti-Semitism. And 58 percent stated that the Democratic Party bears no, or close to no, responsibility for it.

It’s therefore hardly surprising that American Jews continue to show strong support for the Democratic Party; in the 2018 midterm elections, exit polls showed that three-quarters of Jewish Americans voted for Democrats. Despite what President Trump falsely claims, the Democratic Party remains our political home.

Now, Jews are speaking out. Anti-Semitism is an existential threat to our community and we all have a role to play to stop it. The impact is felt communally as well as individually, from increased security patrols to mentally scoping out the best exit from your shul seat for yourself and your children if, God forbid, the worst were to happen. Tragically it is not a matter of whether another terrorist attack will occur, it is a matter of when.

What’s more: This cannot be a partisan fight. Democrats must do more to call out anti-Semitism on the far left, while Republicans must stand up against Jew-hatred on the right.

When 82 percent of U.S. Jews view the boycott, divestment and sanctions movement’s delegitimization of Israel as fundamentally anti-Semitic, those progressives, sadly including a couple of members of Congress, who still support this form of “protest” should listen. Unwittingly or not, they are cozying up to those who want the world’s only Jewish state to cease to exist.

At the same time, Trump’s own rhetoric, equating civil rights protesters and neo-Nazis at Charlottesville’s Unite the Right rally as “very fine people, on both sides” emboldens the violent Jew-haters who look up to him.

That is only one example of the countless times that the occupant of the most powerful elected office on Earth has failed to stand up to racists and anti-Semites. His supporters in our own community must consider how to do much more to challenge this.

As we honor those who were murdered a year ago at the Tree of Life synagogue, we must stand united against hate and redouble our efforts to fight anti-Semitism — wherever it is found, and not least among those who claim to be our political brethren.