T HERE WERE silver linings, of course. A small mountain of flowers, candles and messages of love and sympathy on a street corner two blocks away. Thousands thronging an interfaith service one night later. Wasiullah Mohamed, director of the Islamic Centre of Pittsburgh, telling his city’s Jewish community, “We just want to know what you need…If it’s people outside your next service protecting you, let us know. We’ll be there.”

But behind those linings, the cloud remained. During Shabbat services on the morning of October 27th, a man armed with an assault rifle and three handguns walked into the Tree of Life Congregation, a 154-year-old synagogue in Squirrel Hill, the heart of Jewish Pittsburgh, and shouted “All Jews must die!” He then murdered 11 Jews and wounded six more people in the deadliest anti-Semitic attack in American history. The shooting’s sole suspect is Robert Bowers, a 46-year-old whose social-media posts reveal an obsessive hatred of Jews.

The massacre occurred a day after Cesar Sayoc, a 56-year-old, was arrested in Florida, suspected of posting pipe-bombs to critics of President Donald Trump. Mr Sayoc owned a white van festooned with pro-Trump stickers; he attended at least one Trump rally, where he waved a sign reading “ CNN Sucks” (he is alleged to have sent bombs to the news network).

Americans have since been embroiled in a furious debate over responsibility for these attacks, and fearful that Messrs Bowers and Sayoc are not just angry loners, but harbingers of a new era of violence inspired by politics. A friend of Mr Sayoc’s told the Washington Post that the alleged bomber ignored politics until Mr Trump made him feel “that somebody was finally talking to him.” More than 80,000 people signed a letter to the president calling the synagogue massacre “the direct culmination of your influence.”

Mr Trump condemned both the Pittsburgh slaughter and anti-Semitism more broadly. His credentials on the issue are strong. His son-in-law is Jewish and his daughter converted to Judaism before their marriage. He is a strong supporter of Israel. But Mark Pitcavage of the Anti-Defamation League ( ADL ) notes that white supremacists like him in spite of that. “They say, ‘He’s not one of us, but he’s good for us’.” The ADL has noted an increase in anti-Semitic incidents over the past two years.

Whether knowingly or not, the president has used anti-Semitic tropes. In 2016 Mr Trump’s final campaign ad featured George Soros, Janet Yellen and Lloyd Blankfein—a rich donor to liberal causes, a former Fed chair and a Goldman Sachs boss, all Jewish—while railing against “global special interests…that don’t have your good in mind.” His frequent condemnations of “globalists” carry a faint echo of “rootless cosmopolitans”. There is a gulf between this stuff and Mr Bowers, who called Jews “the children of Satan”. But in some places the worldviews rhyme.

Mr Bowers said that the Hebrew Immigrant Aid Society, a group that helps refugees of all ethnicities, “likes to bring invaders in that kill our people.” He posted conspiracy theories about Mr Soros, to whom Mr Sayoc sent a bomb. The belief that white people are at risk of extinction from non-white races, manipulated by Jews, is the core American white-supremacist belief, notes Mr Pitcavage. Matt Gaetz, a Republican congressman, tweeted that Mr Soros was funding the caravan of Central American migrants heading north. The bomb intended for Mr Soros prompted Kevin McCarthy, the second-most-powerful House Republican, to delete a tweet warning that Mr Soros, along with Michael Bloomberg, a former mayor of New York who is also Jewish, and Tom Steyer, a billionaire Democratic activist and donor who is of Jewish descent, were about to “ BUY this election!”

Democrats have in the past laid similar charges against prominent Republican donors such as Sheldon Adelson (who is Jewish) and the Koch brothers (who are not). But while the substance of the charges may be similar—rich people exerting too much influence over the political process—the framing is different. A few hours after Mr Bowers went on his killing spree, the FOX Business Network aired an interview in which Chris Farrell of Judicial Watch, an activist group, asserted that the caravan was being funded by the “Soros-occupied State Department”. That echoes the white-supremacist belief that America is run by a “Zionist-occupied government”, and turns Mr Soros into what Jews have always been for anti-Semites: string-pulling aliens working to undermine the country.

None of this means that a new era of political violence is at hand. The 1960s and 1970s, today remembered as a golden age of bipartisanship, were rife with bombings, street battles and assassinations. What is different now is that after past tragedies, presidents have seen it as their role to comfort the afflicted, and do their best to unify the country. Mr Trump, by contrast, called for unity, then attacked the press (“the true Enemy of the People!”), railed against “globalists” and chuckled at the thought of imprisoning Mr Soros.

A recent study by Lilliana Mason, of the University of Maryland, found that around 9% of Republicans and Democrats believed that using violence to achieve their political goals was at least “somewhat justified”. While 9% may seem a reassuringly small share, it adds up to nearly 30m Americans.

They ought to pay a visit to Squirrel Hill, where traffic halted as funeral processions wended through the narrow streets. Condolence messages abounded in shop windows. Police tape cordoned off streets leading to the Tree of Life. Just inside the main entrance to the Jewish Community Centre stood a slender FBI agent, watching everyone who came through the doors.

Cathy Samuels, the centre’s communications director, said that, like other Jewish centres around America, Pittsburgh’s has received its share of threats and bomb scares. But she does not want to see the introduction of metal detectors or armed guards. “We see ourselves as Abraham’s tent, open on all sides,” says Ms Samuels. “I hope that the positive change that will come out of this is that we love our neighbours. And I’m not just talking about the Jewish community.”