The US suffered two mass shootings in less than 24 hours over the weekend, both of which appear to have been motivated by racism.
Former President Barack Obama called on Americans to "reject language coming out of the mouths of any of our leaders that feeds a climate of fear and hatred or normalises racist sentiments".
While he didn't name names, it's likely he was referring to the current President, who regularly engages in anti-immigrant and Islamophobic rhetoric.
But does Donald Trump bear some responsibility for the bloodshed?
- Dozens dead after two mass shootings in the US
- President Trump blames mass shootings on mental illness
- Ohio shooting: Nine killed by gunman in Dayton, Ohio
- El Paso shooting: Twenty killed after gunman opens fire in Walmart
Dr Chris Wilson, a politics lecturer at the University of Auckland who specialises in terrorism and extremism, says there's no doubt he does.
"The rise in frequency of these incidents has been pretty observable since Trump came to power," he told Newshub.
It's a term academics call 'process trace', in which a connection can be drawn between political discourse and actions of the public. Wilson says it's difficult to pinpoint when political bluster turns into inciting violence.
"There's no clear line. Just talking about immigration won't necessarily trigger an act of violence, but the terminology used is significant."
Trump has called immigration an "invasion" and a "flood" - terms also used by the alleged El Paso gunman in an online manifesto. Wilson says when leaders employ dehumanising language to talk about a group of people, it makes others think of that group as an uncontrolled threat.
"It feeds a sense of a loss of control, of the culture changing, of nostalgia for an old America," he explains, adding that ethno-nationalists (which he believes Trump to be) "love polarisation".
He says it gives those who feel uncertain about the state of their country an identifiable target (e.g. Mexican immigrants) and action that can be done (e.g. "build the wall"), while validating those who already held extremist views.
"Before Trump there was a lot of prejudice but it was incoherent, people didn't know how many others felt like they did. There was no legitimacy with which to act out... Because politicians have the appearance of legitimacy, they hold more sway over people."
Trump is hardly the first world leader to engage in this kind of rhetoric. Wilson points to Hindu nationalists, Rwandan politicians during the 1994 genocide and former Serbian president Slobodan Milošević as leaders who have referred to some groups as subhuman, whether explicitly or implicitly. They may not have necessarily told the public to commit violence, but they deliberately inflamed existing tensions - and encouraged whatever actions that implied.
It's an old phenomenon that has been given a fairly new name: stochastic terrorism, whereby acts of violence by individual extremists are thought to have been triggered by political "demagoguery". Google searches for the phrase spiked in popularity in the hours after the El Paso shooting.
A non-American example of stochastic terrorism is the 2016 murder of British MP Jo Cox, who was killed by a man gripped by hatred of immigrants and the European Union - standard talking points from far-right parties like UKIP.
Demagoguery, an accusation often levelled at populist leaders including Trump, Turkey's Recep Tayyip Erdoğan and Russia's Vladimir Putin, is central to the phenomenon.
Dr John Battersby, a counter-terrorism specialist at Massey University, defines a demagogue as someone who "panders to the prejudice of the masses", which can be hard to differentiate from normal politics.
"Every election campaign has demagoguery, but Trump has dumbed it down to a point that's scary and connected with a lot of people who don't want to think too much about things."
However he disputes that Trump is doing anything new by engaging with extremism.
"The United States has a very long history of mass killings from all different corners," he told Newshub. "White nationalism has undulated in the United States for the entirety of the 20th century. It's much longer and more deeply ingrained than just Trump."
Battersby is also unconvinced that much blame can be placed on the President for last week's shootings, saying such an accusation wouldn't hold up in a court of law.
"I think it's too much of a stretch to hold Trump fully responsible, but he's certainly amped up the domestic political scene," he says.
"As much as I want to say he's an idiot, trying to get evidence that points to his responsibility would be very difficult. We all suspect a link but it's hard to prove."
Wilson agrees bringing legal charges against Trump would be a struggle, as he often clouds his true meaning in layers of ambiguity and plausible deniability.
"It would require him directly inciting violence against someone who ended up a victim of violence, or against a particular group."
Both experts agree social media has played a major role in the rise of white supremacist violence, which has found a home on anonymous forums like Gab and the recently-defunct 8chan.
"Any idiot with an opinion can be heard, any stupid manifesto no one would ever have read now gets circulated online," Battersby says.
While terrorism experts once believed radicalisation required face-to-face contact, they now realise the process can happen exclusively online. Wilson says the Christchurch massacre was an "eye-opener", as the alleged gunman had almost no network in New Zealand.
"Everyone's so connected it can happen anywhere, and there's no way security forces can keep up with it. It's quite concerning."
Newshub.
