When President Joe Biden visits the site of a racist massacre in upstate New York on Tuesday, he will confront not only the shocking deaths of 10 black people but a growing sense that extremism is pulling at the fabric of US society.
The trip by Mr Biden and his wife, Jill Biden, to Buffalo will be a grimly routine tradition for presidents who for decades have railed against an unstoppable parade of mass shootings.
Like all his predecessors to varying degrees, Mr Biden has promised to address gun control — or rather the lack of gun control. Like them, he has made barely a dent.
Hastily scheduled before Mr Biden's departure on Thursday for a major diplomatic trip to South Korea and Japan, the Buffalo visit will be a chance to “try to bring some comfort to the community”, White House Press Secretary Karine Jean-Pierre said.
However, what marks out Saturday's horror, in which a white man went to a mostly African-American neighbourhood and reportedly opened fire, killing 10 and wounding three, is that the man apparently wrote a document promoting increasingly widely held white supremacist ideas.
At the heart of the document —— which law enforcement believe is genuine —— was a rant about what is called “replacement theory”, which purports the existence of a leftist plot to dilute the white population with non-white immigrants.
It's a conspiracy theory that, like the QAnon narrative, has spread from the furthest fringes of society to surprisingly mainstream areas —— most notably Tucker Carlson's enormously influential nightly talk show on Fox News.
Prominent Republican members of Congress have also echoed “replacement theory” talking points, which in turn are not too distant from Donald Trump's speeches as president in which he demonised illegal immigrants as invaders, once calling them “animals”.
Mr Biden, who says he left retirement to run for president after he heard Mr Trump refusing to clearly denounce a neo-Nazi rally in Charlottesville in 2017, called the Buffalo killings “antithetical to everything we stand for in America”.
The murders were “an act perpetrated in the name of a repugnant white nationalist ideology”, he said.
Culture war disputes have turned everything from Disneyland to school parent meetings into battlegrounds. And after the leaking of Supreme Court draft ruling that would end a decades-old federal right to abortion, passions are intensifying.
If the ruling is confirmed, power would pass back to individual state governments and abortion would effectively be outlawed or at least severely restricted in parts of the country.
With demonstrations in favour of abortion rights staged at the weekend and the issue looming over November's midterm elections, that means plenty more fuel on the fires Mr Biden vowed to douse.
As the midterms approach, and with Democrats fearing a pounding, Mr Biden has sharpened his own rhetoric, branding Trump Republicans “extreme”.
He has coined a new label of “ultra-MAGA”, referring to Mr Trump's nationalist Make America Great Again slogan, and ruefully seems to concede that there's no one left on the other side for him to talk to.
“Ultra-MAGA” forces, he said last week, “have been able to control the Republican Party. I never anticipated that happening.”
AFP contributed to this report