Horrifying attacks such as the one that killed 11 people in a synagogue in the US city of Pittsburgh on Saturday can sometimes be explained as the work of random madmen but recent terrorism in America has a specific political context with echoes in Australia.
Robert D. Bowers, the gunman who invaded the Tree of Life synagogue during a Jewish circumcision ceremony, was influenced by the particular brand of anti-Semitic hate that is nourished by the so-called alternative right, or ”alt-right”.
Before going on his rampage Mr Bowers apparently re-posted social media screeds attacking Jews and financier George Soros, the Holocaust survivor financier, for funding a caravan of asylum seekers to come from Guatemala to invade the US. The synagogue Mr Bowers attacked was a centre for a pro-refugee group called the Hebrew Immigrant Aid Society.
Other terrorists in the US have repeated similar themes. Cesar Sayoc, arrested on Friday for mailing pipe bombs to Democratic Party politicians and sympathisers, was obsessed by Mr Soros.
This is not to be besmirch the mainstream right, which has often led the way in protecting minority groups, nor to play down anti-Semitism and political violence among African-American and left-wing anti-Zionist movements. A left-wing extremist shot a senior US Republican in 2017.
But identifying a problem is a crucial part of solving it, and the right has a problem. President Barack Obama was criticised for refusing to describe Islamist terrorism as Islamic. Similarly, it is important to acknowledge that the attack over the weekend in the US, along with numerous attacks on black churches and the neo-Nazi protests in Charlottesville last year, were part of a trend which right-wing leaders have a duty to resist.
US President Donald Trump rightly condemned the Pittsburgh attack but he and the extreme right-wing media have an ambiguous relationship with the hate-speech which apparently inspired it.
Just as Islamist preachers making generalised calls for violence play a part in Islamic terrorism, right-wing shock jocks and social media vitriol can plant the seeds for terrorism without actually ordering it.
Mr Trump has joked about violence against journalists and is constantly whipping up anxiety over the threat posed by migrants to white Americans. The Fox Business Network in the US aired an interview airing the alt-right conspiracy theory that Mr Soros was funding the US State Department to bring in more migrants. After the Pittsburgh attack it was taken down.
The debate in America can seem remote because our strict gun-control laws provide the crucial first line of defence against mass shootings such as Pittsburgh. Incredibly Mr Trump said the solution was to arm rabbis.
Yet themes similar to those in the US can creep into our political debate. The worst example is Senator Fraser Anning, who gratuitously used the Nazi phrase “final solution” in calling for an end to migration and railed against “usury,” a word laden with mediaeval anti-Semitic venom.
The topics of law and order or immigration are legitimate political debate but minority groups including Jews can make easy targets. In Australia, the Victorian Liberals are campaigning in their state election next month on the threat posed by so-called African gangs. Immigration Minister Peter Dutton made the hysterical claim that it was dangerous to go out to dinner in Melbourne. Thankfully here in NSW politicians are so far refraining from playing race politics. We must show we can discuss these issues with due civility that condemns all forms of violence and without singling out vulnerable ethnic or religious groups.