When an edited video of House Speaker Nancy Pelosi (D-Calif.) began spreading across the Web this week, researchers quickly identified it as a distortion, with sound and playback speed that had been manipulated to make her speech appear stilted and slurred.

But in the hours after the social-media giants were alerted, Facebook, Twitter and YouTube offered widely conflicting responses that potentially allowed the viral misinformation to continue its spread.

YouTube offered a definitive response Thursday afternoon, saying the company had removed the videos because they violated “clear policies that outline what content is not acceptable to post.”

Twitter declined to comment. But sharing the video would likely not conflict with the company’s policies, which permit “inaccurate statements about an elected official” as long as they don’t include efforts of election manipulation or voter suppression. Several tweets sharing the video, often alongside insults that Pelosi was “drunk as [a] skunk,” remained online Friday.

But Facebook, where the video appeared to gain much of its audience, declined Friday to remove the video, even after Facebook’s independent fact-checking groups, Lead Stories and PolitiFact, deemed the video “false.”

“We don’t have a policy that stipulates that the information you post on Facebook must be true,” Facebook said in a statement to The Washington Post.

The company said it instead would “heavily reduce” the video’s appearances in people’s news feeds, append a small informational box alongside the video linking to the two fact-check sites, and open a pop-up box linking to “additional reporting” whenever someone clicks to share the video.

That didn’t satisfy lawmakers such as Rep. David N. Cicilline (D-R.I.), who took to Twitter to demand that Facebook “fix this now!”

“Facebook is very responsive to my office when I want to talk about federal legislation and suddenly get marbles in their mouths when we ask them about dealing with a fake video,” Sen. Brian Schatz (D-Hawaii) tweeted. “It’s not that they cannot solve this; it’s that they refuse to do what is necessary.”

While Facebook’s actions might provide context and lower the rate at which people will happen upon the video while browsing the social network, they did virtually nothing to prevent the false video’s spread by people who have already seen it: Any user could still like, comment, view and share the video as often as they liked.

In the 24 hours after The Post alerted Facebook to the video, its viewership on a single Facebook page had nearly doubled, to more than 2.5 million views. The video had also been reposted onto other Facebook pages, where its audience was growing even further.

The conflicting responses reveal a key vulnerability in how the Internet giants safeguard against viral lies and blatant falsehoods. The companies run some of the country’s most prominent and powerful sources of information, including for understanding political campaigns in the months heading into the 2020 presidential election. But they have shown little ability — and, in Facebook’s case, interest — in limiting the spread of falsehoods.

Facebook has resisted removing outright false information by citing free-speech concerns, a stand the company reiterated Friday. “There’s a tension here: we work hard to find the right balance between encouraging free expression and promoting a safe and authentic community, and we believe that reducing the distribution of inauthentic content strikes that balance,” Facebook said in a statement.

[Faked Pelosi videos, slowed to make her appear drunk, spread across social media]

Jason Kint, the chief executive of Digital Content Next, a trade group representing online publishers, said Facebook should take a more active role in policing and slowing the spread of misinformation.

The site, he said, is reluctant to give too much power to fact-checkers or content moderators, and many pieces of content can often lapse into gray areas, where people’s perceptions of the material depend on their personal politics.

But with clearer distortions like the Pelosi video, the company should respond more quickly and decisively to potentially stifle the disinformation before it gains a life of its own.

“When they put it into people’s timelines and give it velocity and reach that it doesn’t deserve, they’re helping to spread it,” he said.

“Disinformation can spread faster than true information itself,” he added,” And these networks have bad actors — which, in a scary way on this one, involves people in very prominent positions — who can move disinformation so quickly. I don’t think the people who are charged with getting the truth out there are able to mobilize those networks in the same way.”

President Trump on Thursday night tweeted a separate video taken from the Fox Business Network: a selectively edited 30-second clip focused on her pauses and verbal stumbles from a 20-minute official briefing earlier that day.

[Trump shares heavily edited video that highlights verbal stumbles by Pelosi and questions her mental acuity]

The videos fed into what Pelosi’s defenders have called sexist and conspiratorial portrayals of the health of America’s highest-ranking elected woman. They also resemble political videos that posed similar questions about Hillary Clinton’s fitness during the 2016 campaign.

Pelosi tweeted Thursday night that Trump was “distracting from House Democrats’ great accomplishments #ForThePeople, from his cover-ups, and unpopularity.”

Facebook has an internal software tool to find and demote the distorted video’s online duplicates, but the company could not say Friday how many times the video had been reposted.

With the company’s decision made, Facebook groups reiterated their interest in promoting the distorted video. The Facebook page “Politics WatchDog” — from where the video has been shared 47,000 times, often alongside false claims about Pelosi’s use of alcohol and drugs — hosted a user poll with the question: “Should Pelosi video be taking down?” When a majority voted “no,” the page posted, “The people have spoken. Video stays,” alongside an emoji of a wine glass.

The Facebook page’s owners did not respond to requests for comment. But in a Facebook post, they called The Post “fake news” and said the “independent fact checkers that Facebook uses are pro liberal and funded by the left.”

Among the people who promoted the distorted video before Facebook responded: President Trump’s personal attorney Rudolph W. Giuliani. He tweeted a link to the Facebook page Thursday evening — “What is wrong with Nancy Pelosi? Her speech pattern is bizarre” — then deleted it minutes later. He later referred to it as a “caricature exaggerating her already halting speech pattern.”

Giuliani said in an interview Friday that someone had texted him the video, and that he decided to share it after watching her for the past few weeks when he said she had been “talking funny.”

After his tweet, he said, someone else texted him that the video had been altered. “I couldn’t tell if it was doctored,” he said. “I could tell she was worse than a few days ago. So I took it down [just] in case.”

Josh Dawsey contributed to this report.

A viral photo of Virginia Gov. Ralph Northam (D) overshadowed the first day of Black History Month. As an expert in the history of amateur blackface minstrelsy, I was not surprised to see that a young Northam had a blackface Klansman photograph included in his 1984 Eastern Virginia Medical School yearbook.

I spent a decade poring over blackface composites from yearbooks and fraternal orders, watching cracked film footage and cataloguing more than 10,000 blackface plays at Harvard University. Those plays and Northam’s racist photo show us the centrality of amateur blackface minstrelsy to American cultural life and universities. They show how upwardly mobile white men concentrated white-supremacist political power in the century after the Civil War, using the profits of amateur blackface to build white-only institutions and using blackface performances to articulate to voters their legislative commitment to white supremacy.

They also show how persistent those power structures remain.

Though blackface was the No. 1 entertainment form throughout the United States in the 19th century, it has a particularly notable legacy in Virginia. The first globally famous minstrel troupe hailing from New York City rebranded itself as the Virginia Minstrels in 1843. Dan Emmett, the group’s founder, understood his minstrel troupe needed to project a sense of authentic, stereotypical blackness. Virginia, a state that imported enslaved Africans as a colony as early as 1619, embodied the complex relationship between blackface entertainment, slavery and American culture in a single word. The troupe did not just borrow Virginia’s brand, but shaped it: Its song “Dixie” became the unofficial Confederate anthem.

That legacy can be seen in the history of blackface at the University of Virginia, founded and designed by another Virginia governor: Thomas Jefferson. Virginia was a state built on enslaved labor, and U-Va. was no different. Beginning in 1830, the university would “hire out” enslaved people from the surrounding area. Eventually, U-Va. purchased humans like “Big Lewis” Commodore in 1832 at auction for $580, permanently separating him from his family.

Virginia’s slave empire ended when African American slaves fought for their freedom in the Civil War. After 1865, Lewis Commodore was free. But when slavery disappeared, fundraising with amateur blackface minstrel shows and city minstrel parades emerged. They featured fictionalized blackface slaves and their Klansman counterparts — a pairing on display in the Northam photo — to sustain Virginia’s infrastructure and segregated economy, as well as to inculcate new generations into a form of white supremacy associated with collegiality, school spirit and patriotism.

The era we now call Jim Crow America was named after a famous blackface minstrel character. His signature debut song “Jumpin’ Jim Crow” reached global fame in 1832, but it wasn’t until the 1860s that everyday Americans bought commercially packaged how-to minstrel blackface plays to perfect these racial stereotypes. A new era of segregation, mass culture and blackface emerged, where blackface-imitating pro-Klan movies such as “Birth of a Nation” were the go-to entertainment form for young men.

In Jim Crow’s century-long reign, a strange, visible and highly pervasive world of blackface minstrel shows took hold in nearly every city and town in the United States. Amateur blackface minstrel shows and parades were so central to civic and campus life in 20th-century America that it’s hard to find a university yearbook without a blackface image or a town that didn’t hold such a parade.

U-Va.’s love affair with — and financial reliance on — amateur blackface grew during Reconstruction. A rumor circulated throughout U-Va. that “some of the students are forming themselves into a negro minstrel troupe” to perform on campus and in the local towns in Virginia. In 1886, the official University Minstrel Troupe donated the proceeds of its minstrel show to the construction of the University of Virginia Chapel, where hundreds of couples continue to marry each year. The show, which included a “stump speech” — a stand-up comedy routine lampooning black politicians — also featured a “Berlesque of Mikado,” likely in yellowface.

Throughout the First Klan era, the U-Va. minstrel troupe “sweetly” sang in “darky dialect” to raise funds. During World War I, a university-sponsored minstrel show took place on the white steps of the Rotunda, where Lewis Commodore used to be enslaved. Scores of U-Va. yearbooks named “Cork and Curls” (minstrel slang for the burned cork used to blacken faces and the curly Afro wigs that were signature costume pieces) show blackface was omnipresent on campus.

Blackface was a fundraising and socialization tool for white, all-male, Christian civic organizations such as the Benevolent and Protective Order of the Elks. The Ku Klux Klan and the United Daughters of the Confederacy in Virginia used blackface in raids to confuse victims and in comedy shows to recruit members. In 1924, as Charlottesville erected its infamous Robert E. Lee statue, the Charlottesville Elks Minstrel show ran ads ridiculing black American soldiers. They all solidified the relationship between slavery, blackface, white-supremacist political power, segregation, business and university life.

As late as Gerald Ford’s administration in 1974, the annual Charlottesville Lions Club Minstrel show was still so popular it was recommended in travel guidebooks. It has proved to be a hard cultural habit to break. In November 2002, U-Va. made national headlines when three students arrived at a joint Kappa Alpha and Zeta Psi Halloween fraternity party in blackface. As recently as March 2017, mere months before the horrific events in Charlottesville, the obituary of a member of the Retail Merchants Association in Charlottesville cited his participation in the annual minstrel show of the Charlottesville Lions Club, of which he was a member for 64 years.

When white supremacists set U-Va.’ s lawn aglow on Aug. 11, 2017, the brutal legacy of slavery and Jim Crow that stretched between the governorships of Jefferson and Northam materialized in the plume of tiki-torch smoke. The photographs of the rally mirrored the magic-lantern slides I studied in U-Va.’s library, which depicted amateur blackface minstrel shows that were hosted by Charlottesville firefighters, and Confederate veteran parades between 1900 and 1910.

The young men who encircled counterprotesters and the statue of Jefferson in 2017 were part of an exceptionally long history of clean-cut, suburban, civic-minded, young white-supremacist groups on American college campuses celebrated for their patriotism and public service in the 20th century. Northam’s blackface yearbook spread is a small shard of an expansive and ever-present national story, one that shows how racism defined what it means to be a patriotic, successful and civically oriented white man in modern America.