Weeks later came a lawsuit, based in part on that video, in which the woman and two other protesters say crowd members assaulted them upon Trump's command. And that Trump — among other alleged counts — incited a riot.
Then last week, David J. Hale, a federal judge, refused to throw out the lawsuit, rejecting most arguments by lawyers for Trump and other defendants.
“It is plausible that Trump’s direction to ‘get 'em out of here’ advocated the use of force,” he wrote. “It was an order, an instruction, a command.”
So the case will now move forward. Trump's lawyer did not immediately respond to questions about whether they will challenge the ruling, seek a settlement or prepare for a trial.
But the heart of the dispute — what happened in the crowd that day, and why — comes down to a few minutes of footage and a few key figures: the protesters, two Trump supporters accused of attacking them, and the president himself.
Here is what we know.
Kashiya Nwanguma and the plaintiffs
Three protesters claim in the lawsuit that they were assaulted by various crowd members after Trump urged the crowd, repeatedly, “Get them out of here” and variations thereof.
The first is Molly Shah, who says she was shoved.
The second is Henry Brousseau, a high school student who said he was “punched in the stomach by an unknown defendant,” as Hale wrote in his order last week.
But it's the third victim, Kashiya Nwanguma, whose eviction came to symbolize the rally's violence.
In a widely circulated video, a sea of white men is seen surrounding the black 21-year-old college student, shoving and jostling her while Trump, off screen, shouts: “Get out!”
He had been saying things throughout the rally — “get out,” “get them out,” “get him the hell out” — as protesters repeatedly interrupted.
Nwanguma, who waded into the crowd with an anti-Trump sign, later told The Washington Post that she “suddenly felt the crowd's attention turn to her” after the candidate spotted her and called for her removal.
“None of the people who were attacking me even knew what was on my sign,” she said last year. “I obviously stood out in the crowd based on my appearance.”
In the video, a man in a red Trump hat was seen screaming and pointing a finger in Nwanguma's face.
An older man in a veterans association cap — who would later apologize for his conduct — then shoved the woman, repeatedly, toward the back of the room.
Trump continued with his speech: “You know in the old days, which isn't so long ago, when we were less politically correct ..."
Like the two other protesters, Nwanguma claimed that she was assaulted at Trump's command. She also alleged that racial and sexist slurs were shouted at her from the crowd.
One of Trump's co-defendants tried to have the claims of offensive language struck as irrelevant to the lawsuit.
Hale declined to do that.
“While the words themselves are repulsive,” he wrote, “they are relevant to show the atmosphere in which the alleged events occurred.”
Matthew Heimbach, defendant: Assault and battery
The bearded man in the red cap who was seen screaming and pointing at Nwanguma is Matthew Heimbach, whom the Anti-Defamation League had been monitoring for several years before the rally because of his links to white nationalist groups.
He had spoken the summer before to a gathering of skinheads and others on the fringes of American politics, according to a profile in The Post.
He was once photographed at the U.S. Holocaust Memorial Museum in Washington holding a sign that read: “6 million? More like 271,301.”
Heimbach, who is in his mid-20s and is from Indiana, organizes groups of like-minded whites. He has involved himself in everything from local elections to a grand plan in which the United States is divided into racial territories, The Post's profile noted, with a special area “set aside for people who wanted to continue living in a multicultural society.”
Heimbach acknowledged evicting Nwanguma from the rally, although he has challenged her claims that he assaulted her.
The protester had been disrupting the event for the better part of an hour, Heimbach wrote online after the event.
“White Americans are getting fed up and they’re learning that they must either push back or be pushed down.”
Representing himself in the lawsuit, Heimbach did not seek the case's dismissal like the other defendants did. He argued instead that his comment on race and associations with extremist groups should not be mentioned during the trial.
They were “highly inflammatory,” he wrote, “and his opinions about race relations are irrelevant to the issue of whether he assaulted and battered the Plaintiffs.”
The judge rejected this argument.
Alvin Bamberger, defendant: Assault and battery
The video shows that after Heimbach yelled at Nwanguma, a retiree identified as Alvin Bamberger shoved her.
Then, the 75-year-old shoved her again and again, bouncing Nwanguma through the crowd and toward the exit, as Trump moved on with his speech.
Describing himself as a Korean War veterans association member and grandfather, Bamberger wrote an apologetic letter to a local radio station in the aftermath of the rally.
“I have embarrassed myself, my family, and Veterans. This was a very unfortunate incident and it is my sincere hope that I can be forgiven for my actions.”
He said he showed up to an orderly rally with a few protesters in the crowd, which descended into chaos after Trump took the stage.
The protesters got violent first, he wrote to Eagle Country 99.3. “At one point I was physically knocked down and fell to the ground.”
“Trump kept saying 'get them out, get them out' and people in the crowd began pushing and shoving the protesters.”
Bamberger said he was caught between “white supremacists and Black Lives Matter protesters.”
“I was caught up in the frenzy,” he wrote. “I physically pushed a young woman down the aisle toward the exit, an action I sincerely regret.”
These apologetic words were cited by plaintiffs when they accused him and Heimbach of assault — and again by the judge when he refused to toss the case.
“Bamberger’s letter, quoted in the complaint, confirms that he and others 'began pushing and shoving the protesters' upon Trump’s order that the protesters be removed,” Hale wrote last week, when he refused Bamberger's request to dismiss the entire lawsuit — although the judge agreed that he should not have to pay punitive damages.
Donald Trump and his campaign, defendants: Incitement to riot, negligence, vicarious liability
Trump's attorneys challenged the lawsuit on many grounds, arguing that the future president had no duty to protect the protesters, that he didn't intend for his supporters to use force, and that he may have been addressing security — not the crowd — when he said things like “get them out.”
But Hale rejected many of these arguments, writing that the plaintiffs' claims suggested that the violence was a “direct and proximate result” of Trump's speech.
They hadn't proved it, but their arguments were “plausible” enough to go forward, the judge wrote. Hale granted only one of Trump's requests, releasing him from a count of vicarious liability.
“In sum, the Court finds that Plaintiffs have adequately alleged that their harm was foreseeable and that the Trump Defendants had a duty to prevent it,” the judge ruled, referring the case to a federal magistrate, Judge H. Brent Brennenstuhl, to handle preliminary litigation, discovery and settlement efforts.
In their complaint filed last April, the plaintiffs didn't just cite the March 2016 event at the Louisville rally, but violence at multiple Trump events before and after.
The Post examined some of the same incidents last year: rallies “suffused with the kind of hostility and even violence that are unknown to modern presidential campaigns.”
These included injuries and arrests outside an opera house in St. Louis, brawls at the University of Illinois after Trump canceled a rally there, and an event in Fayetteville, N.C., where “police were escorting a young black protester out of a Trump rally when an older white man suddenly punched him in the face.”
Trump was a live commentator in some disputes, The Post noted, once telling the crowd at a Las Vegas rally he wanted to punch a protester himself.
“Get him out! Try not to hurt him,” he said as a protester was escorted out of a rally in Warren, Mich. — shortly after the Louisville incident. “If you do, I’ll defend you in court.”
An earlier version of this story incorrectly stated that Bamberger called himself a Korean War veteran. He actually identified himself as serving in a veterans association. The story has been corrected.