A former president is wounded in a shooting, the gunman quickly neutralized, and all of it is caught on camera. But for those who don't believe their eyes, that's just the start of the story.

For some supporters of Donald Trump, the failure of the Secret Service to prevent the attempted assassination of the Republican former president points to a conspiracy orchestrated by Democratic President Joe Biden. For some of Trump's critics, however, the details of the shooting don't add up. They wonder if Trump staged the whole thing.

Two dueling conspiracy theories are taking root online following Trump's attempted assassination, one for each end of America's polarized political spectrum. In this split-screen republic, Americans are increasingly choosing their own reality, at the expense of a shared understanding of the facts.

"One screen, two movies," is how Ron Bassilian describes the online reaction to Saturday's shooting at a Pennsylvania rally. Bassilian is a prolific user of social media and has used X to broadcast his conjecture about the shooting. "People have their beliefs, and they're going to come up with theories that fit their beliefs."

Bassilian is one of many Republicans now questioning how the shooter, Thomas Matthew Crooks, was able to climb to the roof of a building providing a clear shot at Trump and whether law enforcement looked the other way to allow the attempt. Bassilian acknowledged that he doesn't have proof to back up his conjecture. But the Culver City, California, resident said many people will be distrustful of explanations until an independent review of the facts is completed.

"It seems highly suspicious," Bassilian said of the attack on Trump and the law enforcement response. "Something was going on that was more than a slip-up."

Authorities have released no information about Crooks' possible motive, though they have said they believe he acted alone. But a lack of details from law enforcement and mounting questions about the Secret Service's performance have led online sleuths to speculate — often in ways that reveal their own ideological leanings.

Some of the claims about the shooting have already been debunked. Despite claims that the Secret Service refused to give Trump extra security before the rally, the agency says it actually increased staffing. A post from someone claiming to be a law enforcement sniper at the rally — who said they were ordered not to fire on the shooter — was discredited after it turned out no sharpshooter by his name was working on Saturday. And a photo that supposedly showed an uninjured Trump after the rally turned out to be a picture from 2022.

Humans have an inherent drive to share information and conjecture following big events like disasters, political assassinations or seemingly inexplicable events — a process experts call "collective sensemaking." Often, experts say, we look for information that makes us feel safe or in control of uncertainty. Trump's attempted assassination is only the most recent example on a list that also includes the JFK assassination, the moon landing, the Sept. 11, 2001, attacks, the Sandy Hook school shooting, COVID-19 and the Jan. 6, 2021, attack on the U.S. Capitol.

Many of the claims about the Trump assassination attempt emerged first on fringe social media platforms like 4chan before migrating to larger sites like X or TikTok, where they were seen by far more people.

"Rumoring under these conditions is a normal thing that humans do," said Kate Starbird, a University of Washington professor who studies misinformation and how people use the internet following crises. Attempts to put the shooting in a political context began within minutes of the shooting, Starbird said: "People tried almost from the beginning to frame the event in a way that benefits their political goals."

Many of those rumors may contain exaggerations, missing context or outright falsehoods that generate conspiracy theories. The misleading information is then amplified by online trolls, politicians, internet influencers and online merchants trying to hawk merchandise tied to the assassination attempt. With few guardrails in place to combat bad information online, such claims can quickly spread, impacting the election in 2024 and potentially persisting for years to come.

The flood of false or misleading information about the shooting will only make it harder for voters to find trustworthy information ahead of the 2024 election, according to Imran Ahmed, the CEO and founder of the Center for Countering Digital Hate, a nonprofit that tracks online misinformation and hate speech. Ahmed blames social media platforms for not enforcing basic content moderation policies and for making the spread of misinformation and hate speech into a lucrative business model.

Social media platforms have recently pulled back from content moderation efforts designed to prevent the spread of misinformation. While some sites like Facebook and Instagram still prohibit information that could interfere with the operations of an election, others like X rely on other users to correct falsehoods.

Ahmed's group analyzed 100 posts about the shooting that were recommended to users on X, the platform formerly known as Twitter, and found that many contained conspiracy theories. Only about 1 in 20 false posts had been flagged for inaccuracies or missing context using X's "community note" feature to add needed information. In two days, the posts had been seen more than 215 million times. Some of the viral posts also contained hate speech, such as those suggesting Saturday's shooting was a plot by Jewish people.

"The algorithms take the most outlandish content and amplify it exponentially until the entire digital world is flooded with conspiracism, disinformation and hate," Ahmed said. As a result, he said, "People seem to feel that they can only fight lies with more lies."

Russian state media and some pro-Kremlin influencers are already seizing on the shooting with content blaming Democrats for what happened or questioning authorities' explanations, based on recent posts from users with ties to Russia.

"Almost makes you think they let it happen and then got rid of the guy because dead men tell no tales," wrote John Mark Dougan, a former Florida sheriff's deputy turned online influencer who now writes pro-Kremlin content.

Russia, as well as China and Iran, have used social media disinformation in the past in efforts to undermine Americans' trust in government and democracy and increase polarization ahead of elections. The goal is to exploit the understandable confusion, anger and concern that many Americans feel following the attempted assassination. Federal officials say they expect Russia and other adversaries to expand their disinformation campaigns targeting the U.S. as November nears.

Conspiracy theories have played an outsize role in recent American politics, and much of the attention has focused on right-leaning theories like QAnon, a movement that claims without evidence that Democrats are involved in a global ring of Satanic, child molesting cannibals. But the onslaught of misinformation and conspiracy theories following the attempted assassination show conspiracy theories know no party.

"They target the left and right, and the same goes for homegrown domestic sources of misinformation," said David Salvo, a senior fellow and managing director of the Alliance for Securing Democracy, a Washington-based group that tracks foreign disinformation. He has this advice for anyone interested in finding reliable, trustworthy information about the shooting: "Check your sources, and check the agenda behind those sources."