Mass murder at a Pittsburgh synagogue on Shabbat appears to be an especially horrific hate crime. Yet we should not think this is an isolated incident, unrelated to other events in the country. The United States is among the least anti-Semitic countries in the diaspora, a far cry from much of Western Europe and the Middle East. But anti-Semitism is on the rise in the United States, as we know from statistical and anecdotal evidence.

In February, the Anti-Defamation League released its annual report, finding that “the number of anti-Semitic incidents was nearly 60 per cent higher in 2017 than 2016, the largest single-year increase on record and the second-highest number reported since the ADL started tracking incident data in the 1970s”.

The report continued: “The sharp rise, reported in ADL’s Audit of anti-Semitic Incidents, was in part due to a significant increase in incidents in schools and on college campuses, which nearly doubled for the second year in a row.”

The ADL tabulated “1,015 incidents of harassment, including 163 bomb threats against Jewish institutions, up 41 per cent from 2016; 952 incidents of vandalism, up 86 per cent from 2016; and 19 physical assaults, down 47 per cent from 2016.”

There are few Jewish communities that have not been touched by anti-Semitic vandalism. In Fairfax County, Virginia, where I reside, the Jewish Community Centre of Northern Virginia was vandalised this month by 19 swastikas painted on the building. It was the second such incident in less than two years.

Social media has become a cesspool of anti-Semitic messages and symbols. I can say from personal experience that social-media companies are less than responsive in addressing complaints and disabling accounts that traffic in such material.

Neo-Nazis marched in 2017 in Charlottesville, Virginia, chanting: “Jews will not replace us.”

The synagogue in Charlottesville was forced to remove its Torah scrolls for safekeeping as neo-Nazis shouted slogans across the street.

There is no single source of anti-Semitism in the United States; it comes from radical leftists bent on destroying the Jewish state and right-wing nationalists who consider Jews to be foreign invaders. Both are increasingly evident on college campuses.

On Friday, coincidentally, Jonathan Greenblatt, head of the American Civil Liberties Union, wrote for The Washington Post: “Campus anti-Semitism has come from across the political spectrum. For several years now, alt-right and neo-Nazi groups have targeted college campuses to spread their hateful ideologies and recruit young people for their movements. The ADL found that white supremacist propaganda on college campuses nearly doubled in the 2017-18 school year from the year prior.”

He noted that radical left-wing as well as neo-Nazi groups are no longer rare on campuses. There is, however, one particular way in which anti-Semitism is being mainstreamed in the United States and in Europe: the propagation of “blood and soil” right-wing nationalism that by definition excludes Jews, whom many nationalists do not consider white. A country defined as white and Christian, one in which foreigners and different ethnic groups are seen as “infesting” the country and diluting its true heritage, by definition casts Jews as a fifth column, as outsiders, as “the other”.

Right-wing nationalism in Europe goes hand in hand with overt anti-Semitism. Sure enough, as authoritarian governments have come to power, anti-Semitism has become endemic in illiberal Eastern European countries, including Hungary — where left-wing Jewish billionaire George Soros is an all-purpose bogeyman — and Poland, but also in Western European countries, such as Italy, which is drifting towards fascism.

One does not have to spit obvious anti-Semitic slurs to be perpetuating anti-Semitic themes — for example, Jews control the media, Jews have too much power. Defining Jews out of the body politic — by defining “real” citizens in racial, ethnic and/or religious terms — is perhaps the most common tactic.

The Pittsburgh gunman reportedly focused his ire on the Hebrew Immigrant Aid Society, accusing it of funding the Central American caravan of refugees, which he dubbed “invaders”. Recently, Donald Trump supporters and Fox News programming, following the President’s lead, have obsessed with escalating hysteria over the caravan — which is hundreds of miles from America’s southern border — and Trumpites have even claimed it is funded by Soros, whose name figures prominently in their conspiratorial rhetoric.

So when American politicians blame Soros for opposition to the administration, or celebrate “nationalism”, or declare the United States is a “Christian nation” — as opposed to a country in which a majority of people are Christian — they are consciously or unconsciously channelling and amplifying anti-Semitism.

No one other than the shooter is responsible for the mass murder in Pittsburgh, but there are many people — including those in public office and in digital media — contributing to the rise of the anti-Semitic sentiments the shooter allegedly shouted. If you think words — especially an American president’s words — don’t matter, think again.

• Jennifer Rubin writes reported opinion from a centre-right perspective for The Washington Post