The New Zealand mass shooting that left 49 dead is part of a disturbing trend: violent acts perpetrated by racists and far-right extremists.

Though the primary gunman has not been named, he allegedly took pains to link the violent assault on two mosques to his politics. Police said that shortly before the shooting, he released a manifesto describing his hatred for Muslims and immigrants.

“The 74-page document states that he was following the example of notorious right-wing extremists, including Dylann Roof, who murdered nine black churchgoers in Charleston, S.C., in 2015,” my colleagues reported. It was “littered with conspiracy theories about white birthrates and ‘white genocide” and “is the latest sign that a lethal vision of white nationalism has spread internationally. Its title, ‘The Great Replacement,’ echoes the rallying cry of, among others, the torch-bearing protesters who marched in Charlottesville in 2017.”

Elsewhere, there are references to President Trump and Candace Owens, a black conservative activist, mentions that seem designed to troll.

The New Zealand violence echoes other high-profile incidents, such as Anders Behring Breivik’s assault on a summer camp in Norway that left 77 people, including many teenagers, dead in 2011, and Alexandre Bissonnette’s murder of six Muslims in a Quebec City mosque in 2017.

And the attack in New Zealand seems to be part of a broader pattern: Far-right extremism is on the rise in the United States and abroad, and it is increasingly leading to violence. As my colleagues wrote last year, “Over the past decade, attackers motivated by right-wing political ideologies have committed dozens of shootings, bombings and other acts of violence, far more than any other category of domestic extremist, according to a Washington Post analysis of data on global terrorism.”

We’ve also seen an increase in the number of white-nationalist and other hate groups. According to the Southern Poverty Law Center, the number of hate groups in the United States has grown for four years, from 784 in 2014 to 1,020 in 2018. (A 30 percent increase in the number of hate groups coincided with Donald Trump’s campaign and presidency, after three consecutive years of decline at the end of the Obama administration.) There has also been a jump in reported hate crimes: They increased by 30 percent between 2014 and 2017, after a 12 percent drop between 2011 and 2014, the SPLC wrote.

News presenters in Australia and New Zealand, along with a rugby star, were among the first to deliver emotional responses to the shootings at two mosques.

There are indications that similar trends are emerging around the world. R. Joseph Parrott, an assistant professor of history at Ohio State University, wrote in The Washington Post in 2017:

“Global white supremacy has been making a comeback, attracting adherents by stoking a new unease with changing demographics, using an expanded rhetoric of deluge and cultivating nostalgia for a time when various white governments ruled the world (and local cities). At the fringes, longing for lost white regimes forged a new global iconography of supremacy.”

Trump and other nationalist leaders are often quick to distance themselves from the far-right extremists who perpetrate this kind of violence. But the fact that the rise in extremism and domestic terrorism coincides with a rise in the number of nationalist leaders around the world seems impossible to ignore.