A woman wears a shirt with the likeness of Donald Trump during a campaign rally at the Erie Insurance Arena in Erie, Pa., on Aug. 12, 2016. (Ty Wright/Bloomberg News)

A news release from the Hillary Clinton campaign on Tuesday morning contained a phrase that would have baffled those paying only casual attention to the presidential election -- and baffled nearly everyone if it had been used 24 months ago.

"On Thursday, August 25," it read, "Hillary Clinton will campaign in Reno, Nevada, and deliver a speech to address Donald Trump and his advisors' embrace of the disturbing 'alt-right' political philosophy." Understanding that "alt-right" might not immediately be understood by readers, the campaign offered a brief definition: "This 'alt-right' brand is embracing extremism and presenting a divisive and dystopian view of America which should concern all Americans, regardless of party."

A lot has been written about the "alt-right," not all of it free of contradictions. At Vox, Dylan Matthews explored the rhetoric and policy ideas that motivated some early proponents of an alternative to the contemporary political right, among them a rejection of democracy and an embrace of isolationism. A more sympathetic frame for the political thinking behind the alt-right was presented at Breitbart earlier this year, before the head of the outlet decamped to run Donald Trump's campaign. At Breitbart, a number of alt-right intellectuals are identified, praised less for their intellectual pursuits than for their willingness to ignore societal norms.

The alternative right has come under fire from Hillary Clinton and establishment Republicans, but it has been seeping into American politics for years as a far-right option for conservatives. Here's what you need to know about the alt-right movement. (Jenny Starrs/The Washington Post)

One of the bylines on that Breitbart piece should offer more insight into the nature of the alt-right as manifested in the presidential campaign: Milo Yiannopoulos. In December, BuzzFeed's Rosie Gray explained how the alt-right was powered by a sense of victimhood among straight, white men combined with photo-editing software and the power of the Internet. If you've ever seen the word "cuckservative" used on social media, you've heard the chatter of the visible, 2016 alt-right. If you've ever seen an image of a green frog wearing a Nazi uniform, you've seen the alt-right's fingerprints.

The goal is often offensiveness for the sake of offensiveness in the way that many young white men embrace. Yiannopoulos does. He gained notoriety in part by championing the Gamergate movement, a dry run of the pro-white-male activism and harassment that now defines the alt-right to many. Gamergate, our Caitlin Dewey wrote in 2014, "was always about how we define our shared cultural spaces, how we delineate identity, who is and is not allowed to have a voice in mainstream culture." That's a good descriptor for the online efforts of the alt-right, too: rejecting the "political correctness" of not misrepresenting data on immigration and refusing to kowtow to those who look unfavorably on anti-Semitism.

Yiannopoulos told the New Yorker that the appeal of the alt-right is that "it promises fun, transgression, and a challenge to social norms." In practice, that fun often looks like online harassment campaigns against women, liberals and Jews.

Anti-Jewish, anti-Muslim and otherwise explicit images riddle the online alt-right. In part, that's because it is partly an outgrowth of sites such as Reddit and especially 4chan, where there's often an unspoken contest to be as offensive as possible in images or comments. But it's also because 4chan provides the same outlet that Gamergate and the alt-right do: An opportunity to say racist, rude things in a way that feels empowering. Fun. Transgressive. A challenge to social norms. Also, a campaign of organized obnoxiousness against a black actress that gets you kicked off Twitter. As one conservative said to BuzzFeed's Gray, "It’s really hard to tease out the genuine white nationalists from the trolls. At a certain point, the distinction isn’t meaningful. If you spend all day saying white nationalist things online but you claim you’re doing it ironically, it’s not clear to me what the difference really is."

Matthew Continetti of the conservative Washington Free Beacon lamented that the conservative movement's efforts to expunge historic racist and anti-immigrant elements were undercut by the self-publishing ethos of the Web.

The castle no longer has walls. The gatekeepers are mostly useless. Yes, the rise of social media may have helped conservatives—it allowed them to investigate, report, opine, entertain, and influence politics and policy by giving them the means to bypass liberal outlets. ... But there is also a cost. As conservative media has proliferated, the authority of any one man or publication or radio show or television network has receded to the point of invisibility. For a time conservatism may have resembled the Catholic Church, with Buckley as pope, issuing bulls and ex-communicating heretics. But conservatism these days more closely resembles Islam, with untold numbers of mullahs issuing contradictory fatwas, with antagonistic schools of thought competing for adherents, with not a few radicals eager and willing to blow the whole thing up.

The alt-right's favored candidate for president is Donald Trump, manifested in its online activism and its deployment of Photoshop to Trump's aid. Trump's strong positions against immigration from Muslim countries and across the border from Mexico coupled with his apparently inadvertent penchant for tweeting racist and anti-Semitic imagery has been embraced by the alt-right (as well as self-identified racists more broadly). His decision to elevate Breitbart's Steve Bannon to run his campaign only reinforced the alt-right's appreciation. In an essay in The Washington Post last week, a former Breitbart employee declared Bannon's ascension a "dangerous seizure of the conservative movement by the alt-right."

That's the appeal for Clinton. By criticizing Trump's relationship with the alt-right, she gets to call Trump racist and anti-Semitic without calling him racist and anti-Semitic. She gets to tie him to what the worst of the community does (not that Trump makes those ties harder to draw). Clinton gets to summarize Trump's worldview in its ugliest manifestation and run against that, and each time some bit of alt-right obnoxiousness breaks through into public awareness, she gets to use it as a cudgel against him.

Campaign chairman John Podesta explained the rationale in a statement to The Post. "We intend to call out this 'alt-right' shift and the divisive and dystopian vision of America they put forth because it tells voters everything they need to know about Donald Trump himself," he said. "Republicans up and down the ticket are going to have to choose whether they want to be complicit in this lurch toward extremism or stand with the voters who can’t stomach it."

In other words, Clinton thinks the alt-right -- which is only tangential to Trump -- can help her beat him, by further drawing Republicans away from their candidate.

And she's probably right.